Excellent score, it seems. Let's just hope it stays that way. It's impossible to tell just how good a condition it is until you put it in service. Let's hope there isn't something hidden that will take the shine off what appears to be a super deal.
I'm with the clean up first crew. Scotchbrite or steel wool and a mild solvent will make a huge difference in your ability to see what lies hidden. Save the stone work for areas that you can see a good reason for it. If there are no dings to stone down, then so much the better. And things that are difficult to move may well free up once things are clean. I wouldn't try to run it too much until I was satisfied that all moving parts are clean and well lubricated. Then you can give it a more fair evaluation. If nothing major shows up, then you definitely got a steal. Great going and I hope that is how things turn out. But even if you have to spend some on a few bits here and there, it's still overwhelmingly in your favor that you got a good or great deal. Many of us would (and should) be envious.