An rv should be well balanced. We need to be careful when we alter things to keep weight in order.
Maybe a 2500 or 2800 Onan would fit. Maybe a compartment alteration might be in order. A good welder might be your friend. You could ask an auto body shop that does fabrications.
Go to a commercial truck scale:
I would want to know how much my rig weighs . Front then rear axle. Weighing all 4 corners to see individual weights would be best but f/r would work.
Reason: If, you need to add a portable generator as you described , plus the weight of the receiver and rack , you have to be careful to not overload the axle rating. Plus you need to think about how you will fuel it.
The more weight added to the rear might lighten the front. If the steer axle is too light it will affect handling. If the axle or tires are overloaded, all mechanical components could suffer. Just be careful when you start altering things on your own.
