Winter camping in my new 2005 Tran-Sport T-2675

So, I am moving to northern Washington state in June and will be living in my camper on my land while I build my cabin. I may or may not get everything built before the snow flies, so I may have to camp through the winter.

What do you suggest I do to best insulate my camper? I have considered spray foam insulation on the bottom, along with skirting and wrapping any exposed pipes, but what else? What am I not considering?

Also would love to hear from anyone who has spent a cold winter in a Sunline!