If the engine and trans are good, I’d be looking at suspension components. Especially up front. These are heavy vehicles and are built like tanks, but those parts also take a beating. I’m at 215k now, and have replaced a good amount of the front end suspension components, tie rods, sway bar end links, UCAs, lower ball joints, pitman and idler. Front shocks replaced with Bilstein 5100’s. Also recently did the intermediate steering shaft, not because it “needed” it, but the little clunking noises had to go and it’s a cheap, easy job. Also upgraded both front and rear sway bars with very nice, and effective units from Hellwig. I’d look closely at the hubs as well but so far mine are good. When the time comes it’s going to be Timken 100%. Good luck.