When you lit the furnace did you first light the stove? If not you may have had an air bubble in the gas lines, and this kept the furnace from being able to light properly.
What I do is first open the propane tank valve slowly, then light the stove, I let the stove burn for 20-30 seconds to flush most of the air out of the line. After that I will light the water heater, furnace, frig, as needed. There may still be some air in the lines, so it may take a few minutes to get a good ignition.
Also if you are running on battery the furnace does not run good on a low battery. Also the furnace fan consumes a lot of power so you may only get 12 hours of run time on an OEM battery.
On more furnace tip; buy a small 1500 Watt electric heater. When you are at a campground with electric just plug it in and you have “free” heat, instead of using your propane, it really sucks when you run out in the middle of the night.
As for the Frig. It operates on 110V AC (shore power) or propane. When operating on propane the control system uses 12V DC (battery) power to operate the system. If I recall correctly when your switch is set to “Auto”, the computer will first try to run on 110V AC power (green light), if it does not find AC power it will automatically switch to gas. Until the computer has a confirmed flame the LED will flash an orange/yellow color. Once you have a confirmed flame, then the LED switches to a solid orange/yellow color.
One more OT (off topic) thing. If your electric water heater element does not appear to work, check your circuit breaker panel. It is very common, for people to turn off the breaker when not using the water heater. Our dealer did it to us, and I do it! This is cheap insurance to ensure that the water heater is not accidently turned on when there is no water in the tank. If you turn on the element with no water in the tank you will burn out the heating element. I have had the issue also when I wanted hot water there was none because someone forgot to turn on the circuit breaker.
Best of times you your new TT.