Generator
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.
Forum Discussion
It appears you answered your own question if you don't use the one you have on your current rig. It boils down to how you plan to camp and if that is predominately with hookups it is not worth the investment to have one onboard. A portable 2K watt genny might come in handy down the road should you need to charge your batteries or power something small when hookups are unavailable.
