My car wonders allover the lane at highway speeds. Lots of play in the steering. Feels like I'm driving a boat. I can move the steering wheel a few inches side to side without moving the wheels. Just wondering where to start looking for trouble.

 

With that much play it is time to replace all the front steering parts.

 

verify tire pressure no not laugh

 

check the rag joints as well.

 

Also check the area around your steering box for cracks, and if you have a steering brace (aka wonderbar). If there are cracks then that could cause unstable steering.

Also, your alignment could be out of whack too. I would replace the steering items as mentioned up above and then get an alignment to see what specs your wheels are at. Camber should be equal on both sides but negative camber is better for handling on the street, same as toe ( 3/32 is a good setting for toe-in), and caster should be as much as possible but with 0.5 more on the passenger side.

 

Throwing parts at it is not an effective way of fixing the problem.
Do this; park car, pop hood. Have a helper sit inside with the key in the run position so the steering wheel is unlocked but leave the car off. Have the helper slowly wiggle the steering wheel back and forth from each side of center within the range where there is play. While they do this get underhood and follow the movement down the steering shaft through the linkages out to the wheels. You will see where there is slop. It may be a combination of things. Fix the problem and get an alignment done. Problem solved.