The heater I have from Northern Tool has a low oxygen/Co2 sensor to shut it off if detected. I have a 10 Ft. propane hose with a inline regulator that I run outside of the camper to the tanks. I don't recommend having the tank inside the camper.
I heated a 24' camper for many years at camp with an electric heater. I kept it set at 60 deg and it would cycle off most of the time. When the temp was in the teens it struggled. Add an electric blanket and you will be most comfy. A 1500 watt heater is rated at 12.5 amps so consider that with your generator.
When my wife and I were full-time RVers ( April '12- May '18) in our 31' 5th wheel (one slide-out) we used one big heater (1500w) in the living room and a small 1000w in the hall outside the bathroom (bathroom door open as the wife hates a cold toilet seat ). Never used the factory furnace other than to run it a little while a couple times a winter just to make sure it worked in case of an emergency. Electricity was free but propane wasn't.
Stayed very comfy even on the coldest days.
One thing to consider about electric heaters is the noise from the generator. If you go that route, I would consider buiding a box for it to muffle it down. Youtube has a bunch of plans for doing that.
a Mr. Buddy heater will only run +/- 12 hours at high settings on a 20 # cylinder.
Winnebago MH's were actually designed to run engine heat to supply heat to the coach on 28 ft and less coaches. I would seriously consider a freeze plug block heater, and a recirculating pump on the heater hose side, and a remote start for the engine. Freeze plug should keep coolant in the 60's with the occasional run to operating temp to really knock the chill off. Pump will provide for heat for a couple hours at diminishing amounts, provided you keep the fan running.
Arduino trickery could result in auto start, low voltage start, a run timer to temp or voltage, etc.
As far as the statement you can't get temp power without a foundation, I've been building over 30 years and never once heard such. You may need a permit, but I've never been outright refused a temp service anywhere unless they had to run a good bit of line and poles and wanted paid first.
Another vote for ceramic heater. We have 2 different ceramic style heaters in our rv we use when camping in colder weather. One for sleeping area and second - for kitchen. Also they're quite harmless, which is good since your kid will be with you.
Try to avoid any type of electric heater with a glowing red element. It's a pure fire hazard. I have had several fail on me over the years.