I put mine in the bed right behind the slider on the drivers side so I can reach through my slider from the backseat and turn on the bottle from inside. My truck has a cap on it too, so it's not unprotected back there. I'm thinking about a remote bottle opener just to make things a little easier.

 

Yeah, Im actually thinking about making a custom holder that would fit in the back seat area between the middle seat and the front cupholder. So i could just reach back and open the valve.

The tank will just go between one of the skirted girls' legs in the back.

 

Just be careful she doesn't compare your tank to YOUR tank. lol She might not be so impressed. Hahahahaha
I'd do that if I didn't need to be able to seat 6 using the bench seats.