The ball joints and tie-rods are probably in need of replacement. If this is the case it should show up with the camper off the truck and be particularly noticeable when turning. If this is the case the truck should not be driven at all until it can be fixed. I have had American trucks and SUV's that needed this work done over as little as 50k miles.
I would also expect the shocks to be shot on any used truck or car. Bilstein 5100's are a good choice.
If you rotate the tires and the problem goes away then you have a tire with a bead problem and this too is a real hazard and the tire should be replaced.