OP, if you aren't familiar with the service history I would immediately change the fuel filters, oil and filter. Those are the most important things on this truck. Fuel filters (one under the bed, one under the hood) every 15K miles without fail. Oil and filter at least every 15K miles or every year (many will say at least every 6 months, but I only drive 8000 miles a year).
At 100K you are due for a transmission fluid change. I've seen videos... I'm going to pay someone else to wear trans fluid!
At 67,500 miles you were due for a CCV filter. If you aren't certain it was done, I'd recommend it. They are $60 or $70 on the internet and very easy to change. Watch a video, its literally 8 bolts to remove the engine cover and then it pops into place.
I forget when they recommend transfer case and axle fluid changes, but again at 100K miles its cheap insurance to put new fluid in.
Drive it hard every once in a while (once its warmed up, of course). These trucks were meant to work, and especially the 6.7 gets a little grumpy if you don't work them. I use tow haul and exhaust brake all the time, towing or empty. Its supposed to be good for the turbo spools (to keep them clean) and it saves on your service brakes. Use good fresh DEF, I prefer getting it from a truck stop if possible. Other than that, enjoy!