Couple comments or questions:
You already know you don't have a 4x4 so no axle swap or CV joints.
That out of the way, first, tire shops that do front end work are notorious for "recommending" parts be replaced that may not need to.
How's the truck drive and is it chewing up front tires?
If the answer is "fine" and "no", then it may not be as bad as the shop says.
Define "replaced pretty much everything" a couple years ago. Did you replace the idler arm? Ball jts? Rod ends? A arm bushings? Pitman arm?
Also, admittedly, you are increasing the shock loading on the steering components with how you have the truck set up. Unless you have a unique setup, TC's generally put little to no additional weight on the front end and many actually unload the front a bit. Now you have tires that are the equivalent of flintstone wheels for the load you're seeing. Thus the tires aren't absorbing near as much shock as the (softer and lower pressure) OE type setup. Example, I run 50-60psi in front tires, heavier truck, OE tire size/load rating. 60psi is plenty even with the camper loaded.
I'd get a second opinion though. Preferably from someone who isn't standing there with a blank repair order while they look at it!