Electric heater vs using furnace in fall?

Need advice from experienced campers since wife and I only started this year and have camped only 10 nights due to P/T job getting in the way after retiring....We have a 2014 Keystone Bullet 285 RLS TT that is 30 ft long. Has a propane Dometic 30,000 BTU furnace that heats well and fast.. We have only camped where there is electric and plan on that being the majority of our camping. When we are camping in fall as we did in October and have chilly nights , would it be more economical to use a small electric thermostatic heater for just the 2 of us in the bedroom and not run the furnace at night until we get up in morning, or even purchase 2 heaters and use most of the time when needed and not the propane at all? I have no idea how much propane we are using to heat since we only camped 5 nights in the fall and haven't used 1 of the 2 tanks up yet.. What do you think? We will of course be paying for propane when needed but not for electric. Also, can the wiring handle 2- 1500 watt heaters -- total 3000 watts approximately which I would estimate would be enough? We are not camping when it is below freezing so that is not an issue for the tanks or water lines... no lower than 40's. Appreciate hearing from experienced TT campers..