It would be more practical to do something like add the CheapHeat unit to the main furnace. Warm air rises, so you would heat your RV more efficiently and evenly using the furnace ducting in the floor. The CheapHeat system adds electric heating to your RV furnace so it doesn't have to burn propane:
CheapHeatResistive electric heating also draws quite a bit of current. It would be much more difficult to get heavier wiring up to the roof than doing the modifications necessary in the lower utility areas of the trailer.
Rob
U.S. Army retired
2020 Solitude 310GK-R
MORryde IS, disc brakes, solar, DP windows
(Previously in a Reflection 337RLS)
2012 F350 CC DRW Lariat 6.7
Full-time since 8/2015