Stewart Gibbs is a studio manager at Mantic Games and answers questions on Facebook for The Walking Dead: All Out War. I was going through one of the threads and Stewart was kind enough to give details on the scenery for the next three expansions. I don’t recall exactly what thread his comments were in but I did save them for future reference:
For the farm, you’ll need 6 fences around 3″ long, a tractor, a barn around 6″ by 8″, and 4 hay bales.
For the prison, you’ll need 5 chain link fences around 4″ long – that’s it for the prison as the rest is the internal corridors which are printed on the mat. You could build a 3D one to match, but you’ll need to wait for the actual mat if you want to match sizes etc.
For Woodbury, you’ll need 2 smoke clouds about 3″ across, 4 lamp posts, 6 stakes for walkers to be tied to in the arena, and a tank around 7″ by 4″. The rest of the Woodbury stuff is four houses, all printed on the mat. They must be small enough that there’s room on a 20″ mat to have a street between them, and space between and behind them for models to move. They can have a few rooms in each, but all of them must have at least one 75mm square room that is used for certain objective overlays.