This is definitely a tough one for me. All of these would be funny to have as incorporating typical GPS instructions and all that, I would think JR would be the most fun, so he's my pick. When you come up to a wreck on the side of the road, he could go all like "AS GOD AS MY WITNESS, HE'S BROKEN IN HALF"
He could also say things like "turn left kid make yourself famous!" "BAH GAWD LEFT/RIGHT TURN AHEAD!" "Aw son of a bitch! You took the wrong turn, damn it!"
But yeah, my pick is JR.