It is necessary to have a generator in a 5th wheel, I know some have them some don't. We are looking to go to a 5th from our class a and we really don't use ours a lot now.
Yes. Use the generator for dogs, the family or just charge the battery. No difference in gen sets for MH or fiver. Costs the same to run them. I guess the class A folks accept the cost of comfort and fivers sweat it. Lol