Here's the Western Europe terrain I'm working on at the moment for Adepticon 2015. This is supposed to represent a typical town somewhere in France or Belgium and I've decided to utilize HO scale European model buildings to save money.
First, many of the European HO manufacturers are slightly underscale from the normal 1:87 scale used in HO scale modeling. Nearly all of these kits are straight out of the box with the exception of the doorways, the interior floors, and (rarely) the building height. I've had to cut down the doors by about 1-1.5mm to make them look "just right" next to 15mm figures. In many cases, I simply cut the door down and then added a small transom above the doorway. The yellow house required cutting off 2mm from the total building height but that was easily accomplished with a dremel in 5 minutes.
The nicest part about plastic HO kits is the architectural details, all molded in different colors. Little painting was needed beyond adding mortar to the brickwork and shading and weathering to the roofs.
The "city hall" building below is a Faller Railway Administration Building, actually part of their take on the Bonn Train Station (this is the "wing" on the real life station, the portion in the immediate foreground in the image below). You can get this kit fairly easily on Ebay (like I did) for under $20, which is a steal for a building measuring nearly 7" long! The roof is removable (simply by not gluing it to the walls, no conversion necessary) and I made two second floor "balconies" inside the building to aid figure placement.
I still need to add propaganda posters and debris to the exterior, as this will be the most contested building in town.
The two houses are both Kibri houses designed for early modelers. This makes them easy to assemble and cheap (I bought these two for less than $25 on Ebay). Both feature removable roofs (again, just don't glue the roof down - no conversion necessary!) and removable second floors. The blue roofed house will probably represent a small inn.
I still need to add hedges and groundwork to their "backyards".
I'm now awaiting delivery for a couple townhouses. Enjoy until then!