Question concerning condensation

Thanks for your insight and experience! I have watched a ton of videos on the internet about others and what they found when they tackled the insulation. Some had none at all, some had insulation that had lost its position, and some insulation was very thin/slight. I have seen how they did insulation installs themselves, but the problem is they only start the video after the shell has been removed, or when the initial problem was water damage, after the walls were removed. I have very little insight on how they removed those vital parts. It is an older 5th wheel and I want to believe that improving the insulation is possible. I'm trying to find a carpenter in the area to see if they have some suggestions. The local RV place wants me to bring it in, but we spent a lot of hard work and materials on constructing the skirting and making cold-friendly plumbing PVC as the drain pipe on the tanks. Breaking it all down is breaking my heart! LOL It has been a learning experience thus far and definitely not for the faint-hearted, comfort-loving, lazy person. I just really want to believe there is a way to reconstruct this rig into a cold-tolerant living space. ANY warnings or suggestions would be appreciated, no matter how seemingly insignificant.