Murf2,
My opinion only...
A "Good Brand, Good Quality" motor home in that age group is surely worth $10,000 if it truly is in good condition. I would offer $9000 with the expectation you will need to invest more to make it work for you, like the generator and such. If they don't budge on the price, then I would pay their price. Maybe they'll meet you half way at $9500.
It would make sense to mount a portable generator in the area where one was originally planned for. If not, then do as I have seen others do and simply have it out on the ground. A full installation requires a starter, an electric fuel pump, remote start panel, and a fuel line into the main fuel tank... too much hassle to consider anything other than an RV generator which comes with all that. An Onan4000 would likely be "that" right generator.
If you are not big on air conditioning, it seems those tiny 2000 watt portable Hondas run so very quiet that you could use it anytime without bothering the neighbors.