reads like you have access to electricity?
if this is true consider placing a small OIL filled or ceramic space heater in the unit and leave it ON 24/7.
my preference is OIL filled and a 1500
watt version that has setting for 600 and 900 along with full on.
then set the main trailer thermostat to 45-48 degrees for a few weeks and keep track of lp gas usage.
IF you are going through lp gas too quickly, lower the themo to 42, the lowest setting available.
open all the cabinets and drawers to better circulate the space heater warmth.
install a bypass valve at the water pump and use THAT to circulate a little rv antifreeze to ALL of the pipes/lines.
BYPASS the water heater and leave it EMPTY.
poor 1 cup of rv antifreeze into each sink drain AND the toilet bowl (above the valve)
leave all three tanks with MINIMAL fluids, don't ATTEMPT to open the drain valves in frigid temps.
then before trips quickly fill the fresh tank and FLUSH all the faucets to clear.
which send the pink stuff to the wash water tank.
THEN open the water heater bypass and fill the tank, then turn ON the gas to heat the water.
add a few gallons of drinking water (jugs) and go camping!
IF you keep the inside 40 or so 'pinking' the water pipes isn't necessary,
but IF the power should go off (and the trailer quickly get cold) this pink stuff will save your pipes.
IF you wanna go camping and don't plan to shower, just leave the lines PINKED and skip using the fresh water tank...
then consider using a porta potty or bucket/bags instead of the toilet for that business.
once u have several warmer days (45-55) OPEN the outside shower fixture and DRAIN that water.
then CLOSE the bypass valve to the outside shower which cuts OFF the water flowing into that pipe.
next year CLOSE off/bypass the outside shower faucet PRE WINTER season.
i use my trailer every winter (usually in the south) and right now it's approaching ZERO outside, where i'm parked.
since the fresh tank is ~1/2 full, the heat set a tad higher (52) but otherwise follow all the steps listed above.
no problems with frozen pipes or tanks in many years following these steps.
IF you are keeping the trailer at 30 or warmer inside (in prep for camping) the LCD TELE IS FINE!!!!
check the owners manual or operating specs (online) MOST of them are rated to ~zero
(some lower) degrees when not in use.
teles FREEZING is mostly a MYTH.