We used a 110 plug in at my brothers and got along fine. We are a 50 amp motorhome. We just used propane for the water heater and frig. Didn't need heat, but could have used A/C. Instead we used the ceiling fans with windows open and had a floor fan rotating- moving air seems cooler. In your case you can use your furnace for heat. Just be mindful to not use many thing at once.
As far as filling propane, do a google search when you get there, or you could do a tank exchange if you use 20# tanks. If an onboard tank you can do an extend a stay and then use the 20# tanks which are easy to refill/exchange. Many grocery stores, hardwares etc have that. Some gas stations have propane fill as well as farm coops. Or, if you drive by a large propane dealer they usually will fill for you. Many of the Flying J truckstops have on board tank fills available.