Being in Nevada, the law for passengers in the back is:
Must be over 18 year old
I’m going a bit beyond that
The seats are boat seats on a pedestal
I tapped & bolted through the deck & frame for 2 bolts, 1 bolt lagged into a 4 x 4 mounted underneath, final bolt through the deck into aluminum flatbar
The seatbelt mount is going be tied into the front of the bed [waiting on metal]
I added a piece of 1 x 1 to the bottom of the back gate, after losing a 1/2 gallon of windex through the back gate