Re: What about the dog?
Okay dog harnessing for the Jeep, I found, is unique from other vehicles. I tried the harness that the shoulder belt loops through, and my poor mutts were constantly getting tangled in the damn thing. You see, trail riding is different from going over the highway to the park.
So, I got a short strap of nylon web (length determined by height of your dog) and sewed a loop in one end just like a leash handle and sewed a leash hook in the other end. Just a VERY short leash basically. BUT I made the length such that when you loop the leash around the bottom crossbar of the seat frame and pass the hook through and handle loop, you can snap onto Rover's collar.
I made the length of this rig specifically so Doggie can stand on the seat without hanging over the side of Jeep. My dogs can now sit, stand and lay down with only one strap to deal with. No getting tangled in the seat belt or complicated harness straps. Yet, he doesn't have enough lead to fall out or jump over the side.
It's really pretty simple. Nothing is more dangerous than having Spot howling, hanging by his neck while you're trying to negotiate an obstacle. If you leave him free, he will bail the second the Jeep feels like it is not as stable as he would like. Consider what will happen if the edge of a 50 foot drop off is just a few feet from his side of the Jeep. Strap him in.
I trail ride with two hyperactive greyhounds and this set up works for me. Csvaugh, from this BBS, saw my set up when we rode together at the Rosser Rendezvous.