That's quite the conundrum for sure.
I'm from the upper midwest and spent a winter in NW WI, building a house, coincidentally. But I had it dried in by Halloween so that helped. We were living in my parents "summer cabin" (mobile home) during the summer and fall and ditched that for a rental house around Halloween.
If it's a mild winter, it will be a significant improvement over an average or cold winter up 'der near da UP, but will be a challenge.
Question is how much "power" do you have? You're not going to get much else powered with 1 - 30A campsite circuit and several space heaters running.
Here's something I would 100% consider (off the top of my head at least).
Since you're still camper shopping, get a toyhauler with an open garage, low ceiling model. Most "living space" per length of camper you can get. No slide outs preferably, or leave them closed.
Then install a pellet stove in the back end of it. Direct vent is easy, to fab up a cover that the vent can go through an existing opening, like an existing wall or ceiling vent. Worst case, you could cut in a vent into the wall and then repair it in the future with any number of vents or little access doors.
Easy to stand up some stone veneer or Durarock for a floor/surround. Buy 2 pallets of pellets. 1 to use, 1 for weight in the back of your truck until you run out of pellets at 8pm on a Sunday night, lol, and let it cook the place.
As a bonus, you have backup heat with the camper furnace then, and you can re-purpose the pellet stove into your new home.
And make sure you have a genny for backup if the power goes out.
You could mount a fan from the ceiling in the hallway in place of a ceiling light, to circulate air to the front bed/bath.
Skirt it well and make sure it's parked out of the wind.