So I just got off the phone with Alde about installing radiant heat in the truck camper, replacing my furnace. Basically, unless I want to totally gut the entire camper and redesign the cabinets and bones, it's not possible. Well.. It's possible it just wouldn't be efficient. The new builds are specially designed to circulate air without any fan. My camper cabinets were not designed that way so it would basically just be a really expensive floor heating system. Better to go with the electric mats I first mentioned.
Alde referred me to a company called Aries engineering in Hillsboro, OR that make the electric mats. Though he did say it's really not appropriate for boondocking. Which is how I plan to spend the majority of my time.
I think I'm going to have to bite the bullet and buy a pair of heated slippers. Not nearly as luxurious but i guess this is just another sacrifice I will have to make by choosing to live this life. That and a hot bath. And a dishwasher. And a washer/dryer. I'm really going to miss those creature comforts.