I like the idea of a root cellar underneath an old farmhouse in the countryside. Don't think having tunnel systems in the cities would fit Chernarus, they are coastal cities after all, and the water table would be very close to the surface.
everything in Arma2 is based on the mouse wheel. the menu is contextual and will change as you try to interact with different objects. for bandaging yourself, try right clicking on the bandage in your inventory.
I already have a house in Day Z. There's a school nearby, shopping is convenient, and even a fire station just down the road. Too bad about all the "visitors" on my lawn...
fire from indoors, the walls muffle your shots. same for forests and in the rain. firing an AK in the open is just begging to be killed by zombies or bandits.
earning a medic armband would be a pretty cool addition. say, 25 player bandages/transfusions and no murders in the last 4 game hours? hard to be a bandit medic if you can't murder people.