IMO, if you're going to be camping at electric sites, you may be better off getting 1 or 2 space heaters instead of fixing the furnace. We pop-up camped for 9 years before our HTT and used the furnace maybe twice. 2 space heaters were sufficient to heat the whole pop up. On our HTT now, we use the same 2 space heaters and have run the furnace maybe once.
If you're boondocking, then the furnace will come in helpful, but only until the battery (or propane) runs out. We did that once in our pop up and the battery ran out overnight, causing the furnace to just blow cold air because it couldn't light...