The 3.5 engine is a pain. The rear exhaust cam will move no matter where you put it and space is limited. 4 individual cam pullies that dont stay where you put them, along with angled timing marks = pain in the rear. With water pump IIRC it pays 7+hours labor. Change everything associated with the T/belt; pullies, tensioner, etc. Last one i did it had 1 bad pulley, leaking tensioner, and a separated harmonic balancer, all with only 55k miles. Might as well change belts if they are original. I was able to still do it under book time but it was close. Make sure the shop knows what they are getting into with this truck. There is an updated crank sensor reluctor ring assy, may want to look into that as well.
Spark plugs arent the easiest as well, as the intake needs to be removed. Pays 3 hours.
Buy parts at worldpac or OEM. Dont skimp out.