Worthwhile to insulate/enclose underbelly without heating?

We lowered the axles screwed on 11/2 x 2 pvc brick mould to the frame. then 2" high density foam, then coroplast. The extra R 10 made all the difference on a rig we wintered over in Canada.
First
Heat traced all waterlines, used old waterbed heat pads on tanks ran them up to where they could be plugged into camp power or inverter.

Heat tracing isnot expensive with cut to length 5w/ ' SS cables. If you did freeze up,the tows alternator through the inverter, or shore power would thaw them quickly.