That is a fairly easy repair, but then it's also not all that difficult to find 80's Trek 600 series bikes. In my area they show up in Craig's list quite frequently for around $300. If the bike had other issues, then I would just look for a new one rather than try to repair it.
As for forcing a 130 mm hub in without cold setting... For what it's worth, I've ridden tens of thousands of miles on old Treks with 130mm hubs and I've never had a problem like that.
Steve