wiring question for a 1996 cab over

[Anewway]

Getting everything ready for a trip to see the eclipse in Wyoming and I'm having some wiring questions.
I understand the 4 pole connector on the camper requires a hot from the truck battery, a ground, running lights and possibly a brake light.
My question is about the wire from the truck battery to the camper. What gauge wire should this be?

 

[Rusty]

There is a question for Brian at the factory if I've ever seen one

the older campers...70's...the wire was merely a piece of 12 ga. wire in the lanyard.....it was just carrying the 12v currrent to the lights...no load to speak of....except the refer...which drained the truck battery in a heartbeat

with the loads of todays electronics et al...I'd be wiring it differently altogether...something to chew on