Intro

Just a quick note to say I live in England, meaning there are very few guns and no extreme weather conditions to worry about. There's good farming land but nowhere to go to that is completely isolated from civilization. Also I say 'shop' instead of 'store'...

Supplies

Food

-Between us, our group will have enough tinned/other long lasting food to last us 2 or three weeks.

-As soon as the 'apocalypse' starts we will all fill up as many containers as we can whilst the water supply is still functioning (but the plan includes being next to a river anyway).

-Seeds

Weapons

-Lots of knives

-A Katana (a proper one!) which one member of our group knows how to use

-A professional catapult

-I aim to make a bow (properly, not a twig and some string)

-Cricket bats and other blunt weapons.

-Javelins

General equipment 

-Map of the County

-Compass

-Matches

-Rope and String (enough for tourniquets)

-Medication (painkillers, antibiotics, etc)

-Toothbrush (hygiene is important!)

-Family sized tent (each family)

-Sleeping Bags & Blankets

-Tools

-Binoculars 

-Note: this is all stuff we either currently have or will have soon. I know there are other highly useful items which I will aim to loot during the apocalypse.

The Group

I admit we don't have anyone brilliantly useful in our group, but everyone is able bodied, fairly strong and quick at learning (hopefully) -no elderly people or young children. The one specifically useful person is the guy with the Katana since he does loads of martial arts/cadets/hunting and stuff like that. He's also the most prepared and the most eager to kill stuff (!). We will begin with friends and any of their close family members who want to come with us but in the long run we aim to expand in to a large, self sufficient community (taking in more survivors, repopulating, etc).

The 'Base'

Our base will be the Cathedral in our city (it's barely a city, by the way, so not too many population worries). It has:

-Strong walls/doors
-Large capacity (easily suitable for storage and future community)
-A tower which will function as watchtower, signal tower (to rescuing military forces, hopefully) and last line of defense- there is one stairway to the top and a fall which which would easily kill you if suicide became our only option...
-It's next to a river
-It's a Cathedral so it's filled with Pews which will be smashed up in to planks and used to barricade doors.
-It has a courtyard which we can plant crops in and defend easily.
-Within walking distance of all of us.
-In the centre of town. This means it's close to all sorts of useful places: shops filled with food, a police station, a gun shop, etc. This also means there is a fairly large population to worry about, but I'm hoping that most of the residents will go back to their homes on the other side of the river or leave the city and become zombie-fodder somewhere else while we're on our way to the cathedral.

The Plan

It's important to remember that at this stage the apocalypse may be a few continents away at this stage, so we have plenty of time and we will be able to travel in safety. Plus we'll get an advantage over most other people since most people won't worry about it until the zombies are hammering their doors down. 
When the zombie outbreak begins we will get the aforementioned supplies together (The Katana bloke and I already have emergency kits) and fill up water containers. We will communicate with each other while our mobile phones still have charge to arrange a meeting time (since most of the plan will occur in the first day our mobile phones will still be useful and we will use them to arrange meeting times and backup plans before we meet up). Then we will all set off to our respective meeting places. I will try to convince my family to come- because that way we don't have to split supplies, they don't have to try to survive in a suburban house with not much food/water and there's the whole 'emotional attachment' thing- but if they refuse to come with me then I won't stay with them. If I'm on my own I will take my supplies, get on my mountain bike and meet up and if my family come then we will walk (we don't have 4 bikes) and we will take all of our supplies. Then I will meet up with my cousin and the Katana bloke (who is a friend of mine, by the way) a couple a roads away, we will head down another couple of roads to our school (a central place to all of us- about 5 minutes away for me, 2 if I'm on my bike) and meet up with the rest of the group: My group of friends who made this plan plus any of their family members who decided to come. When at the school we will raid the D.T. storage room for useful tools (some of which can also be weapons, obviously), the food tech rooms for long lasting food, the sports centre (which is next to the school) for more food and, unless it is overrun, the supermarket (which is also next to the school) for all kinds of stuff (batteries, hygiene stuff and mostly food). When we have finished at the school we will head out the front entrance and down another road to the school playing fields. The school stores a lot of its sports equipment here in a rusty crate thing, which we will be able to break in to with our tools (or if we're lucky we'll be able to take the keys from the P.E. block at school, which will also get us in to the sports centre) and get the javelins (there is enough for a class of P.E. student so there will be one for every member of our group). The javelin is a great weapon too, it can be used blunt to club the zombies, it can stab and it can be thrown. Once we have the javelins we will head down the path between the playing fields which will take us alongside the river. We can take this opportunity to scout the cathedral; if it is overrun then we can use one of the back-up plans, or improvise (hopefully we won't have to improvise!). If it's clear then we will proceed down the path alongside the river to the bridge. if the bridge is overrun then it doesn't matter because there are a load of canoes kept next to the river which are guarded by a foot-high fence, a thin chain and some tarpaulin. Once we cross the river we will head to the cathedral (a 2 minute walk from the bridge) and go inside. There are 4 potential occupants of the cathedral: A) No-one- we just walk right in. B) Survivors who beat us there- we will try to reason with them, if they are worse equipped than us then we will threaten them, if nothing works and they keep us out then we will resort to a backup plan C)Friendly christians who are awaiting the rapture- we lie and tell them we're christian, and they let us in. D) Zombies- depending on how many there are we either fight or go to a backup plan. Once in the cathedral we will smash up the pews and barricade all doors (or at least one area of the cathedral, it depends on quantity of wood and time) then we will climb the tower, barricading doors behind us, and paint a big sign on the roof to let military helicopters know we're there. Then we have 2 options depending on how far through the event of the zombie apocalypse we are: if it hasn't reached my city yet (if it's at this stage then it's worth pointing out we wouldn't have raided shops, barricade doors etc; we'd get arrested) then we'll stash our supplies and buy more supplies from local shops, and pretend we're homeless or awaiting the rapture as an excuse to stay in the cathedral, ready. If the zombie apocalypse is in 'full swing' then we'll dig in and ration food to survive in quiet safety while the initial mad panic blows over. Our food supplies should last us at least a couple of weeks.

Mid-Term

When our food and water supplies get low we will venture out of the tower and create better barricades on the doors (so the doors are strong enough to hold back hordes of zombies but able to let us in and out), totally de-zombify the cathedral, plant seeds in the courtyard (depending on the time of year, obviously), raid local places for supplies, take in more survivors, generally survive. It's impossible to plan in great detail for anything other than the short term though, so this is very vague.

Long-Term

Take in enough survivors to have a fully self sufficient, as-safe-as-possible community. Build up huge stores of food and weapons, extend barricades to include outside the cathedral, right up to the river where we will have toilet and washing facilities, all protected from zombies, build useful machinery- providing we take in a survivor(s) who knows what (s)he's doing- such as a generator, water purification system, establish a basic form of social-democratic government/leadership so everyone is catered for equally and decisions regarding the community can be made. If we have a scientist or doctor then we could even begin to analyse zombies to find out more about them.

Really Long-Term

This depends on whether the government and military are still functioning, if the military have set up camps or forts for civillians then we can hopefully be saved (either by being found via out 'help us!' sign or by hearing of a place and travelling there if logistically possible). Then the military can thin out the zombie population whilst scientists work on a cure, all the while we're living in a fort with rations and protection. We have to hope that the government don't just decide to hide in a bunker and nuke the cities...

If government has collapsed then it will be a long time before a cure is found, the zombies may die out/be killed off or humans and zombies may reach a natural 'harmony' as seen by all predators and prey in nature. The good news is that there will be a lot of procreation!

Final Note: I realise that the ease of this plan succeeding depends on the zombies: if they're slow, dumb zombies then this plan just might work. If they're fast, not-so-dumb zombies then survival becomes a real challenge. If the zombies begin to evolve to become stronger and more intelligent then we're screwed. Personally I believe that a zombie apocalypse is theoretically possible (albeit incredibly unlikely) but they wouldn't technically be zombies, since to be a zombie you have to be undead, which I do believe is impossible. If I'm right then it becomes way easier to survive, since there are more ways to kill a zombie- destroying any vital organ will do (that's why they're called 'vital') and they can also starve and be killed off by the cold.

 Anyway, that's it. Any constructive criticism is much appreciated, if you're wondering where my backup plans are then I probably just haven't got round to posting them yet.