Been working through what appears to be the common petcock issue. There were several things going on:
1. We'd find leaking fuel when parked
2. Bike would sputter and die like running out of fuel, then wouldn't crank again until I drained carb- I assume it was being flooded by excess fuel
3. Hydrolocking (Guy we bought it from thought piston was frozen, but based on how easy it was to unfreeze, I believe it was just hydrolocked.)
Bought and changed petcock, flushed crankcase with oil to make sure there was no fuel in it (equivalent to about 3 oil changes) and cranked it up. Starts right up, idles great. Let it run for a solid 15 minutes. Shift into gear and it immediately dies. I adjusted idle, but it still happens.
Didn't want to do this more than once bc I didn't want to screw anything up, but I did get it to go by shifting into first and immediately hitting the gas. Once it got moving, it ran perfectly. Coasted fine, responded well to throttle, shifted up and down with no problems. At this point I had the idle set high enough that in first gear idling I was moving. Reached down and lowered it, and as soon as it slowed to the point of not moving, it died.
So I guess the summary is idling in neutral: fine. Idling in gear while moving: fine. Idling in gear when not moving: dead.
Can't get local bike mechanics to touch it b/c they can't get parts. Trying to get one to at least help me diagnose it, but that's not working either. Closest Sym dealer is an hour away.