Thank you for the tips, Jeff! I will certainly be following all your suggestions as I start making the streets. I hope mine end up looking as good as yours. 
I took a little side project yesterday and today since I brought up where to put the houses that don't fit in my town. I removed the supports and plywood/Homasote roadbed that were abandoned on the other side of the layout when I rearranged the track a couple years ago. Here are a couple photographs of the area now. That allows a space of 10 inches from the lower tracks and the support for the upper level.
The diagonal lines on the lower particle board show where I was considering installing a siding early on. Now I don't recall why I didn't. 
I plopped down a few sections of 1-inch Styrofoam to raise the buildings a couple of inches. They can sit there for the time being. I have more important things to do on the town; streets, etc.
