It is often helpful to verify actual amp output from the truck to the camper batteries. In many cases it can be a good less than folks anticipate. Thus the rationale for much heavier cables from truck to camper by many owners.
I think the best way to decide what does what is with a meter capable of measuring amp draw. The rule of thumb in the RV industry has always been not to use inverter power to heat or cool. Brief microwave use can skirt around that rule, although a lot of stuff that goes in our microwave takes a good bit longer than 2 minutes. As with everything RV, “it just depends”.
On the big high end buses I worked on, which I think can actually approach “all electric” for a brief period of time they have 10 of those 125 pound batteries and two 3,000 watt inverters. 🙂
Steve and Andra
2012 F350 6.2 gasser SRW LB
Fab Fours front and rear in case we run into a rhino
2019 Northstar Laredo SC
