The only thing I'd look over we'll is the rest of the truck on a "high mileage" TV, but not the engine. Especially little electrical gremlins and trim (locks, windows, door handles' AC/heat)
100k miles is not much on a Diesel engine is it hasn't been all modded out (intake and exhaust are good mods, but beyond that, it may have been an unrestrained idiot behind the wheel with high power mods/tunes). I have no fears on my 210,000 mile '01 F-250 PSD getting me to where I'm going as much as I do having the windows roll down or the wipers stop,wiping.