The Resurrecto RB-1 is fun to ride on this stuff. The big fat tires make it easy to be sort of sloppy when it comes to line-picking, so that's nice. These specific tires (Panaracer Col de Vie) are the standard, high-value 650b tires. They're like $20 and really good quality. I'm always surprised by how well the lame looking tread holds onto dirt. I wouldn't want to do high speed dirt cornering on these tires, but for climbing on dirt and general trail riding they're surprisingly competent tires. It's an inverted tread, so they roll wonderfully on pavement too. And at 50 psi, they're super comfy.
I really need to work on the shifting/drive train on this bike though. The old Suntour cassette is used. The chain is used; the front chainring has a slight wobble in it, and I really don't like how stiff the Shimano bar-end shifters are. It's noisy and the shifting sucks, even by my super low standards.
I think I'll end up getting a new cassette and chain. I have Suntour barcons. I'm not sure what to do with the wobble in the chain ring. It's not an old chainring. I wonder if I can finesse the wobble out with a large mallet.