We're headed out for a 2,500 mile endeavor in a week and a half. Don't really plan to do anything we don't always do (whether it's 100 miles or 1,000). I check tires, torque lugs and the hitch bolts, change the oil, stock up on spare fluids, etc...
For me, it's more about what you do along the route than before you go. The longer the day, the more intentional I am about checking oil along the way, watching the tires, etc... Going a couple hours, you can readily check that stuff once and be fine. Going hundreds of miles in a day, you need to take the time to do it a little more often.