Does the unit have maintenance records? You could end a engine and generator oil sample off to Blackstone labs or I think Amsoil does the same thing for analysis.
9500 miles isn't much but the folks might have been living in it while parked for extended lengths of time. Lot's of snowbirders down here in Florida have decided to just store their units down here and then bring it out of storage in November when they get down south. Me I don't have the money to do that so I make the trek back and forth each year. Will be heading home a week from today.
I see you are in upstate NY. If the unit is their I'd make sure they had the unit winterized properly or you could have some plumbing issues.
If the owner is willing I'd have him plug it in if he has a pad or take it to a near by campground and see all the systems in operation (fridge, ice maker, AC's, furnace, vent fans, stove, oven if equipped. Then unplug to see if everything is good to go when dry camping (read inverter) and of course run the generator.
Went for a walk and remembered about engine coolant. Try to find out whether the unit has been converted to OAT (read longer interval coolant) or regular diesel engine coolant such as Fleetguard. If the engine does not have OAT in it stop by your local diesel shop, or Cummins/CAT place and get some test strips and test the coolant also. If the engine is a Cummins ISB engine no need to check coolant with strips.
Do you know what transmission is in the coach? Most likely a Allison 5 or 6 speed. Both are bullet proof. Likewise with this see if it has Transynd fluid in it. I'm almost sure it does my 07 M/H came with Transynd in it some folks have never converted and still use Dextron.
