It's obvious that the coach was not driven much but used some. Generators like to be used. 650 hours over 11 yrs. is not really that high. Generators can go 1,000's and 1,000's of hours before a rebuild.
Diesel genny's can go 10's of thousands of hours before a rebuild (hearsay). Not really sure of a gas genny, but if it's half of the 20,000 hours of a diesel genny for a rebuild, 10,000 hours is a long time away.
Good luck,
MM.
Mr.Mark
2021.5 Pleasure Way Plateau FL Class-B on the Sprinter Chassis
2018 Mini Cooper Hardtop Coupe, 2 dr., 6-speed manual
(SOLD) 2015 Prevost Liberty Coach, 45 ft, 500 hp Volvo
(SOLD) 2008 Monaco Dynasty, 42 ft, 425 hp Cummins