My knight was setup the same way. Several outlets shared the same breaker on the inverter. Nice when heading down the road or boondocking, to power electronics/etc. But not so nice to run the heaters thorugh. I took time to find out what power was on which breaker including non inverted power and which leg of the 50A. By doing so I learned that I could run a 1500watt thermostatic controlled heater in the bedroom area on a 30A site which helped keep the overall coach warm. If I was on a 50A site add another 1500watt pointed towards the front door, but I had to use a specific set of outlets to avoid poping the breaker and stay off the inverted power.
I never tried to use them to avoid the furnace, I still wanted it to run to keep everything underneath from getting too cold (did not heat the bays but it shed heat onto the water system/etc.)