When we play we use the strategy where you stay in the room under the stairs in the main house. we leave the comm room closed for all of the lower rounds and if we get good guns we leave it closed the whole game whether the box is in the comm room or not. We will open all of the other huts and grab the perks in the early rounds so as to have them for when it gets hairy. Then we will put two people facing forward and one on each side looking out for the guys in the middle. Always put a bouncing betty by the thompson so that if you do need ammo you can go to the thompson. If a zombie does get to you the betty takes care of that one.
For the levels with the dogs always use bettys first. have everyone save there bettys and go one at a time and set then directly in the doorway. the dogs will get hit with the bettys first then the others in your party can lay there bettys down. so on and so on.
If you do need to go to the box in the comm room remember you can always go back to the room under the stairs. put two on one door and two on the other . Try to get a crawler that way you can roam around and pick up all of your perks you may have lost.
Well thats it for now .