Really, building all those extra trailers isn't required (you get points for them later if you really want the points) but the money has to be spent. I've added a section to the rules about "hunting land" so if you're kinda stuck on how to spend all that money and the lot is FULL then just buy some land! :)

That redneck mansion is cool, by the way! I downloaded it a while back and made it into apartments for the neighborhood. ;D Part of this challenge though is to not have a two or three story living space. SO, just buy some land if it's too crowded!