Thoughts for you:
-Check all other LP systems - stove and HWH. As Ron asked above, are they running normally?
-Are your tanks full?
-Did you open the tanks slowly?
-Could have a little moisture in the propane tanks and, at the temps you were camping at, the regulator might freeze up.
-Were you on battery or AC? If the battery is low, it might not have enough power to run the fan fast enough anymore to activate the furnace's sail switch or possibly to run the thermostat correctly.
Bad control board:
-If you reset the furnace by turning it off then on again and it works for a while before turning off then I would guess it’s could be a bad control board.
Bad thermostat? Consider replacing with a digital.
Hope this gives you some ideas.
DW, 3 Kids and our Goldens
2012 Shamrock 233S
2008 Toyota Sequoia 5.7L 4WD