From what I have seen a pickup 5th wheel has smaller kingpin than a road tractor so the adapter wouldn't work for this application unless you made it with the right size pin. Like M5 says most of the ones I see have the ball mounted behind the plate if they have both on it. You have enough truck you don't have to worry to much about it being past the c/l of the axle. See a lot of them around and have considered going to one myself as my pour pickup is overloaded most of the time. Used to be you could pickup a single axle tractor here for about $3,500 so can't buy a good pickup for that. Think they have gone up a good bit lately tho.