I think your furnace is also heating your basement area where if you just get a Electric Heater or portable gas heater you may open yourself up for freezing your tanks and water lines. Perhaps worth checking into before stopping the use of the propane furnace.
Electric Oil Filled type heaters works great for us in our OFF-ROAD POPUP. We will use the Mr Buddy heater when off-grid. The propane furnace in our case is way too big to use in our small footprint floor space. It runs us out of there with too much heat no matter where you set it and sleeping with the loud blower motor just a few feet away from the beds wakes me up everytime it turns on...
I have been thinking about replacing my propane furnace for a Hydronic type hot water system heat source.
Roy ken