For shaking at speed and wandering, it can be anything in the suspension. The first thing to check is where the looseness is coming from. Jack it up so the tire is off of the ground and grab the top of the tire, shake it back and forth and see if it moves, if not try the other side the same way. If you get movement on the top of the tire, somewhere in that side of the suspension is suspect.
On our P30 the shakes and and wandering came from worn king pins.