When it comes to older airheads, I generally prefer to buy a high miler that's still in regular service over a low mile barn find.
The high miler that's still in service will generally have had the maintenance required to get it there.
The low mile barn find is going to need the replacement of everything rubber, which means a whole heck of a lot of mechanical labour: pushrod tube seals, main seals front and rear, cam seals, possibly trans input seal. etc etc etc.
If it wasn't stored "just right" it'll likely require a rebore and oversize pistons, too. Or an aggressive hone and new rings if you can't afford to do it right. Either way, it's probably going to need a ton of work and $$$.
That honey of a red R50/5 I posted recently was on ibmwr for a decent sum. It couldn't be built for the amount the guy was asking. That'd be money very well spent for any potential buyer.