Auction purchase. Service recommendations?

Hello forum I am a new member with my first diesel powered truck. I have a daily so this Will be used for the weekend cruising and towing racecars to the track acouple times a year. Had purchased through Carmax auctions under wholesale price so it was a good priced buy. This has 124k miles but I have no service records or any information on the truck. The only thing I have an issue with is the alignment. It pulls to the right and the only tire with cupping ware is the front passenger. I’m wondering if it’s any ball joints or tie rods. I usually work on cars so know nothing about the suspension geometry of this truck. I will be taking it to a local shop to do a pre buy inspection as I have 7 days to return. Just incase it’s something catastrophic. But in my eyes it doesn’t seem too bad. I would like to know what’s recommended as I have no records of the truck. It has a gooseneck attachment in the bed so kind of worries me about how much it has been towed with the 68rfe. I will be putting new tires and alignment as well as front/rear differential fluid. Tranny fluid, oil change and fuel filter. The serpentine belt looks like it should be changed. And per service manual it’s 100k so might as well do that but doesn’t seem like any leaks on the engine besides transmission oil pan. Everything on the truck is functional as far as exhaust break and 4wd. Any recommendations?