I've also used media like movies (Saving Private Ryan, Band of Brothers, etc) and games (Call of Duty series) for sources on what European buildings look like!
I have always scratchbuilt my structures, just because I'd rather not spend $30+ on just the ruins of a building. I use thin wood (basswood or scrap thin plywood) cut to shape and covered with drywall (plaster) compound. Then carve in any stone or brick work patterns. If you want a stucco wall, just sand the plaster down until you get the desired texture. I use balsa or basswood strip for heavy timber beams, rafters, soffit, joists, floor and roof boards and even wood shake shingles--nothing beats real wood grain, plus you can realistically battle damage these items. You can even burn the wood slightly and "soot up" the plaster with a match to get a realistic burned out look.
This method has always worked really well for me and I can build a section of a house in an evening or two.