lights flickering:
remove the headlight switch and plug from the dash.
closely inspect the back of the switch, and plug for burn marks/melting.
if you see ANYTHING funny, replace both. the headlight circuits on these trucks was at their limit when new. 30 years later, they just can't handle the load put on them.
most of us also put relays in the headlight wires when replacing the switch and plug, this makes the switch a low current trigger for the relay because all the current for the headlights then goes through the relay.

play in steering:
get an assistant to sit in the cab. you get up in the hood and reach down to the steering column. you will see the piece coming out of the cab, and then the intermediate shaft that comes out of there and down to the steering box.
hold the lower intermediate shaft and have your helper rock the steering wheel side to side. feel for any play. there should not be any.
if there is, you just found the problem.
there is a teflon bushing in there held in place with a spring steel clip. when the clip breaks, the bushing will slide up into the upper column and eventually fall off the lower column.
unfortunately this is not a replaceable piece you can buy. ...
but it is repairable. i have fixed quite a few of them.

 

On the steering issue - have done that test with the intermediate shaft and determined that all the play is in the steering box. Any band aid solution or adjustment or do we need to bite the bullet and get a new box?

Electrical wise, most are saying to replace the alternator. Might give it a try.

 

you can try adjusting the bx, but in my experience that is just a temp solution. sooner or later you are going to have to replace the box.

 

I got the box tightened up today. It did take some of the slack out of the steering but it's developed a little memory steer. Might loosen it up a hair tomorrow - might not. I'm not really worried about wearing the box out more since we'll have to be getting a new one within the next couple months.