I ended up hiring an electrician to move the panel. And glad I did - he removed the panel board and we found additional buried splices and live wires pinned between the paneling and the wall behind it. So this turned into a rather large job - took him around 6 hours. And that was even with my "help!" ("Helping" mostly consisted of rerouting wires in the crawlspace and attic.) I can sleep much better at night knowing that most of the major problems with the wiring have now been fixed.
I like working on my house, but I've also come to realize that some projects are better left to the pros for safety and/or time reasons. Thanks to all for helping me work through my options. Still plenty of rewiring left, so I'll be asking more questions, I'm sure.