How 4-season are 4 seasons Lances?

Grit dog wrote:
^your last sentence says it all.
You’re not going to do “better” than starting off with a 4 season camper. And with that it’ll handle below freezing temps and running water, to a point. Basement model TCs are decent here if they have or you can improve heated air exchange to the “basement”.
Reasonably the furnace will keep the camper warm down to single digit temperatures. But it will chew thru LP and battery power FAST.
Keeping the water on will just be a test. It’s not magic. But more challenging in below freezing temps. But you get what you put into it.
I was able to use our AF camper with no mods for better heat/air circulation in single digits at night 20s and sunny daytime but that was real close to the practical limit I’m sure.

A little diesel heater is a GREAT idea. And something I would do 100% if planning on any sort of regular cold weather use. And they’re relatively inexpensive. Just need to address the logistics and install.
For efficiency this would be your primary heat and the mouse turd toaster would be the redundant portion since it’s much less efficient.
An engine coolant radiator hookup in the camper is a bad idea. Scratch that one off the list. I suppose it’s possible but in no way practical. Same for the suggestion of plumbing from the truck diesel tank for a little add on diesel heater. Another solution that doesn’t solve a problem but only creates complexity and potential for failure points.

Thanks for the response. Yeah my reasoning for the Diesel heater is to limit what you are saying. One, if I can use diesel to supplement heat for travel, I can extend the time the generator can run. I've also seen some set ups with LiFePo batteries that use the truck to back up or primary charge the systems. My use case is 3 or 4 days at a time with a lot of travel in between so I mainly need 24 hours of boondocking typically.

I get your reluctance on complexity, and maybe I'm looking at it with my Engineer brain and thinking its just a matter of the right bits and pieces. I'll keep it in mind. Of course I'd do it in a way that didn't jeopardize the engine/truck systems (again more complexity).