when do I rebuild the front end

My dive buddy has a 2001 4x4 4door 150,000 miles hauls scuba and camping gear and 12' enclosed trailer

new tires (i assume tire pressure is correct)
he was told after a wheel alignment that "its adjusted all the way"
laying under the truck, the steering rack "moves"
ball joints and tie rods look tight while sitting under load
ran truck years with one air bag on left side; right side broken bag


THE PROBLEMS
He is not comfortable with the handleing anymore. It used to drive straight for miles and feel safe.
I drove it and it pulls to the left pretty badly (we didn't check pressure last night)
When the steering wheel is turned back and forth, the steering rack "moves" in the rubber do-nut mount, I know it is supposed to...but how much. It deflects like 1/8th--less than 1/4 inch I guess.
I think he needs new rear leaf springs becuase of the heavy loads and the "flipping of over leafs??"
He found a better set of rear air bags to help with heavy loads and 12' trailer.
he is planning to replace the shocks
when do ball joints need replacing?
how would he get more alignment adjustment back into his suspension?


150,000 miles sounds kinda young, but he does hunt and haul heavy scuba gear with it

help us
thank you

 

has anyone wore out a stock front end or have any thoughts

 

Under those conditions I would not be surprised if shocks were worn out, ball joints were worn out, and possibly tie rod ends worn out.

Test the shocks by bouncing the truck hard up & down while it's parked and see whether it keeps bouncing, or stops immediately after you let up.

Test the balljoints by removing the tires and inspecting/ manipulating the control arms and see if there's wear/play in the components.

Seeing spring sag is more a visual thing. Does the truck just look like it's sitting low?

If you get a service manual at an auto parts store, it'll give you some more tips on identifying worn components.