Truck to camper wiring questions

I use a 250 amp blade switch, mounted on the bolt that tightens the positive battery terminal on the truck. Then a 10 gauge wire to a lift gate connector, wired direct to the camper batteries. with a pair of 10 gauge wires for the ground. THe 10 gauge wire seems to be enuff, but I'm sure 8 or 4 g would be better. I only open the switch to protect the truck battery when I am going to be dry camping in one spot for more than 2 or 3 days without much sun to run the solar panels. What I like about the blade switch is that it is simple to install, reliable, I can take advantage of the truck battery capacity, and there is no measurable voltage drop. What I don't like is I have to open the hood and do it. I use a combo deepcycle/starting battery in the truck and a pair of 6v golf cart batts in the camper with 200w solar.
I have never ran the batteries down enuff that the truck did not start, but I figure if I did, it should still start the generator to charge it back up.

https://www.awdirect.com/knife-blade-battery-switches-for-side-terminal-batteries/battery-tools-accessories/