You need a fresh water tank heater
I have a smaller freedom elite (23U) and your fresh water tank sounds like the same pit that mine is. Yes there is virtually no insulation in that area, and my tank is under the dinette bench seat so it is really hard to get a heater in there to keep and the water lines warm. I have dismantled the dinette seats so many times I no longer even bother putting the screws in the tops to hold them down. You can have a dealer install a fresh water tank heater, along with grey and black water tank heaters to keep them from freezing. I called Thor and they said the stuff is available and any dealer or rv shop can install it. The blanks are there ready for switches on my power control panel by the entrance.
Trying to remove the fresh water tank to insulate it looked impossible to me and I was afraid trapping condensation and creating a mould zone. I might have designed it differently.
I live in an area where freezing temps happen early and leave a heater on inside when I am trying not to drain the system because we are still camping . So far it has worked out for us. Get the actual schematic from Thor for your motorhome so you can understand your plumbing system because the Thor supplied owners manual is so generic that it is useless.
Rocky
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