We drive from northern Virginia. We usually stop for a 5 hour nap/rest at my in-law's house in SC but next month we're planning to drive straight through. I'm expecting 16 hours including pit stops. My youngest is autistic and while he's done great on long trips before, his recent behaviors have me thinking we'll all be happier if he can sleep through most of the drive down.
We road trip a lot. My kids are currently 9, 8, and 6.
Things that work best for us are:
-Leave in the evening, let the kids stay up a little later than usual then pit stop and encourage sleep. Take away the devices, toys, water bottles, etc to help them drift off.
-For us, first person to drive stays up very late the night before and naps the afternoon of departure so they start the trip well rested. Bring ear plugs (and maybe melatonin) for the passenger so they can sleep before it's time to switch drivers.
-Pack picnic food rather than stopping at restaurants for meal. The kids have been cooped up in the car, they are not ready for restaurant behavior. We look for larger rest stops with room to run for meal breaks. We have picnic and let the kids run around a little. When a good rest stop can't be found, we look for large shopping centers and park in the back of the parking lot. Then we'll use the restrooms at a fast food place and buy drinks or a snack there.
-Have a bunch of activities and distractions planned, but don't give them to the kids all at once. bring them out slowly. A big hit with my kids is silly face stickers, I can usually find them at Michael's. I'll give them a piece of paper and the book of stickers and say "Make a face like you just hugged Mickey Mouse" "What would you look like if you had to change your brother's diaper" Silliest face, scariest face, etc.
- Headphones, if the kids will use them!
- Each kid gets their own small blanket so there is no fighting
- If the car stops, every single person tries to use the potty. No exceptions, not even Dad

- Look for rest stops along your route before you leave. In my experience through the southern end of I95, most rest stops are well lit, often have police presence, and the facilities are clean. We have napped many times under a street lamp at a rest stop!