I've started with the window wrapping, found some old windows, pulled the glass out and built tight frames for them to go in front of my windows making them double paned.
I set it up so that they can be removed individually for nice days, and I won't have to keep using double sided tape and plastic. So far only the kitchen windows are paned, so I have a ways to go, and may just build frames for plastic wrap for the others.

I definitely have to replace the basement floor all the way to dirt and I think I'll replace with concrete and subfloor heating when I do. I should be able to have a hot water heater running off hybrid power to supply both water and pump power, so it should be pretty cheap to run. But that's at least a year away, maybe more.