When I purchased mine it had not been started or even gone inside for 3 years. After replacing chassis batteries, I removed engine ECM fuse, cranked engine for 30 or so seconds 3 or 4 times to get oil up to camshaft and valvetrain. Reinstall fuse and it started right up. .....did same with generator. I've ran it about 6k miles and all seems OK.
Thankfully there was no mice/rat damage to anything.
If I was in your situation, I'd check all tire psi, fluid levels, brake and turn lighting, drive a few miles and pull over somewhere safe and check engine compartment, walk-around coach to make sure ain't nothing stupid happening......
1999 American Eagle
ASE med/heavy certified technician
ASE advanced diesel certified