Guess I should add, re: editing the guitar parts.... yeah, I generated the solo track for the entire song, and just edited it down to the places I wanted it. Had to fade the bits and pieces in and out sometimes (not always), but I am happy with the result.

Next time I'm going to use envelopes in Reaper. Bob just told me about them. I looked them up. Oh yeah! That's what I need! Those will be very useful. Where has it been all my life?