FYI, I have a 1995 Fleetwood Mallard model 19n (21 ft total) tandem axles and it's about 4000 lbs. It's in as good of shape as it has ever been except the paint is wearing a bit and needs new awning which I rarely use. When I bought there was no evidence of water leaks anywhere and that is why I did, knowing it needed new brakes and bearings and charger/converter so now it is like new and pulls like it wasn't even there. So it has been good for 25 years and still going.
2014 Chevrolet 1500, crew cab, srw, 2wd, 4.6 gas, Stock class V, 1995 Mallard by Fleetwood model 19n