Eric,
I'm doing it partly for fun, and partly just to learn the program, but there's also a room in that exact part of the house where the roof difficulty is that is currently just a large unused attic that I'd like to finish off. I don't know how much more I'll be using the program beyond our own house, so I doubt upgrading to pro would be a worthwhile investment. May still do it, though, At some point my wife and I would like to design and build our own house.
Jo Ann,
You're right. I should attempt the 2nd floor before proceeding further. At first I thought it'd be a simple thing to throw on, but now that I see how difficult it's going to be I think I'll do the 2nd floor first. Maybe it'll present some answers. And if not, at least I'll only have to figure the roof out once. I'll post some more pics of the house soon.