You may need more than electric heaters in the DWF area or you may not. I suggest you assume you'll need more than electric and get yourself a 30# tank and an extended stay hookup for your furnace unless you want to drive to a propane dealer to fillup your onboard tank.
We spent two winters in the hill country west of Austin, one was mild the other I was at the propane dealer once a week for most of Jan and part of Feb. We also ran two 1500 ceramic heaters 24-7 and the heat pump when the temps allowed...