Other than 2011 Landmark and Bighorn models that have a receiver hitch option, Heartland does not recommend any sort of rear bumper mounted hitch or platform. Likewise, our frame supplier, Lippert, also does not recommend it.
That said, many owners have, at their own risk, had others design, fabricate and install receiver(s) on the back of their Heartland 5th wheel RVs for things such as bike racks, storage/generator platforms.
If a problem develops that is traced back to unplanned stresses on the RV, those problems will not be covered by Heartland or our suppliers.
Some Heartland owners store their portable (3,500 watt and smaller) generators in their truck bed and set it out when needed.
Jim