Go RVing

Our TT is not designed for heavy winter camping. The underbelly is fully exposed with all 3 tanks showing and drain pipes etc. There is also no heat ducted down nor any tank heaters. To live in it through a good winter (temps down to teens, windy, a few snows), what is the quickest and most efficient way to insulate? Adding insulation and encasing it in plastic between the frame rails? Just doing a skirt around the outside? What are your thoughts?

Anyone like to camp for the weekend or maybe even living in an RV? Hoping to build this place up with experience and technical knowledge like the other place.

The small circular dish on top. It’s maybe 4-6” in diameter and pointed straight out. There are several here with similar.