Camper is 1999 Shadow Cruiser Model 700 truck camper pop up w/small Dometic 3 way Fridge, 3 burner atwood stove top and can't recall furnace brand(its buried in snow right now). Not sure of wire gauge between inverter and truck battery but appears to be same as battery cables. The wires didn't heat up when we were running the freezer. We have solar lanterns, portable propane heaters and head lamps so on board DC is mostly a luxury I think? I'm a tech dummy for sure but have done a fair bit of back country camping by canoe in the Maine Woods and by sea kayak on the coastal islands(Registered Master Maine Guide). Thanks again for all the great input