Camper battery modification wiring questions.

[Awann99]

Hi Fellas. I am planning a long distance camping trip with my 1969 gmc 1500 and vintage camper shell. I will be off the grid most days. I know I could ice down some coolers but I want to be able to keep my food cold effectively and not worry about running out of ice. My plan is to add a 12 volt fridge and an aux deep cycle battery under the hood to power this while the truck is off. My only problem is wiring the battery to the truck and making it charge correctly and also be able to separate the current from the regular battery so I can crank the truck in the morning. I read that deep cycle batteries don’t like to charge off a truck alternator. Is there something I can add to make it charge effectively off the alternator. Has anyone else added this kind of setup to their truck? How did you wire it up? Any help would be much appreciated. Thank you.