Yes, the Terrain is different. I go with tree stands, farm fields, hills and large rocks, wagons, stales, livestock, and of the Angry Town's Folk. Think more of a town or village, than a ruined city.
You don't actually have to make each tree. Just a flat patch and declare it as a tree section. That way you can still use the tree rules and still be able to move you troops freely though it without knocking over the real trees.
Also, ponds and swamp sections slow movement just as a ruined building would. Also, you could declare it has thick tall grass and reeds around it. It also would block line of sight.
Intact buildings are easier to make that ruins. Go on the internet and look for pictures of doors and windows. Print them out and glue that to your boxes. If you live in the USA, you can go to the Post Office and get boxes for free. Simple paint, and printed doors, windows, and such; and a town is born quickly.
Here's a link for Hirstarts.com. (I love this site) On this page, you'll see some printable doors and wood planks. That window ones are kind of fancy for a town, but may be be useful. http://www.hirstarts.com/plans/plans.html