@Cort
If you already have a 7-Way Trailer trailer connection at the back of the truck you might already have 30 or 40 Amp charging circuit installed. Here is the diagram I used when adding the tow controller to my 1997 Tacoma which included adding this 40amp charging circuit. you're interested in the 12v hot lead and Chassis Ground pins for charging your GoalZero.
You would need to wire up an adapter to connect the 10 gauge 12v line and 10 gauge Ground line to your Anderson plug.
I'd start with a trailer wiring connector like either of these:
7 pin blade -
https://www.etrailer.com/Wiring/Hopkins/H20046.html
7 pin round -https://
www.etrailer.com/Wiring/Bargman/WG54006-043.html
If you don't have the charging circuit on your truck or otherwise want it in bed you could buy the Battery connectors, 40 amp fuse holder, 40 amp fuse, enough 10 gauge 2 conductor wire to get from your battery to bed mounting location and Anderson APP plug. The ARB Fridge wiring kit would be a good starting point (
https://www.quadratec.com/products/96010_1011.htm ) then either switch the ARB socket for your Anderson APP plug, or use it and wire up a 12v screw-in to APP adapter.
Boort