2017 Fleetwood Bounder

Tongue weight is not at all relevant here; the hitch is only rated to pull (and push, when stopping) up to 5000 pounds. It's not at all unheard of for motorhomes to have trailer hitches with comparatively reduced tongue weight ratings (e.g. 350 pounds tongue weight, 5000 pound hitch rating). If the hitch were designed to be able to pull a heavier vehicle four-down or on a dolly, the ratings would reflect that.

Can you get away with it? Maybe...but it's neither the safe nor the sensible way of doing things. Please don't try it.