Few questions for a guy not wanting to end up dead

[NearlyDead]

 New to the game here. I read the Wiki and some of the recent posts and I have played a couple of sessions.
I have a couple of questions.

1) I have noticed that a lot of the buildings: Malls, Police stations and such are boarded up and I cant get inside to search around. I have been in 4 different areas and found this pretty much the same (luckly I found a club to hide in before my moves were up) Is this the case all over? If so, how do civilians level up thru shopping?

2) I have a policeman character. I know you level them by killing zombies but I have only 6 bullets. Since police stations, malls and such seem to be unenterable, are there other places I can find ammunition?

3) Last, do you have to be a member of an organization/guild group? I have seen a lot posts about militias and organized groups. Can a lone character have any hope of surviving and leveling?

Thanks all
Ned the Ratcatcher
Philo Muddgrubber

[Vantar]

Welcome to the game! Here some answers I hope you find helpful:

1) Buildings that are barricaded beyond the Very Strongly level are unenterable from the outside, Malls, Police Stations, Hospitals and other such buildings are frequently barricaded the the Extremely Heavily level (the highest level in the game). Civilians level up by killing zombies, healing and reviving  survivors, spray painting certain buildings. For a full list of ways to level up read the Experience Points article on the wiki.

2) To get into buildings that are barricaded past Very Strongly you need to get the free running skill witch will let you travel building to building with out going outside. The only other place to get ammo is the fort armories but I believe both forts are currently under siege. Your best bet is to find a suburb with a low zombie presence and find an accessible Police Station and load up on Pistol Clips

3) Lone characters can survive on their own with out too much difficulty assuming they find safe places to sleep (for humans) or weakly barricaded buildings (for zombies). My current human character was group less for the first 6 months I played and have found that groups don't really make it easier to survive just more interesting when you are alive while with my zombie character found that leveling up goes faster if you find a hoard to follow.