Oops, thought I'd responded to this. I would pass, because of the A/C, generator, and toilet removal. I know those generators run around $2K, the A/C is, what? $1K installed? I can't imagine the toilet and tank would be cheap to replace either... so you'd be looking at $3500 or more just to get it back to stock. And who knows what else was changed; it's obvious the owner didn't have any qualms about altering it. Oh, and it looked like the satellite antenna was where the A/C used to be, but I could be wrong about that.
One hopes those mods were done correctly - holes sealed properly, wires capped, etc. I'd go over it with a very fine toothed comb.
1995 Airstream Classic 30' Excella 1000
2014 Ram 2500 Crew Cab with Cummins 6.7L Diesel
Sold but not forgotten: 1991 Airstream B190
Sold: 2006 F-250 6.0L Powerstroke Supercab