We drive from Chicago so I can’t give you any tips regarding your route but I can tell you what worked for us for traveling with kids.
Each kid gets a pillow, blanket, and backpack sized carry on for whatever they chose to bring to keep the occupied. My kiddos are older now but when they were younger it would usually be a book, notebook, colored pencils, coloring book, Nintendo Ds, iPod/mp3 player. Now their phones keep them occupied. I would also pack DVD players and dvds. Screen time isn’t great, but it’s worth the peace it brings on a car ride - plus it balances out that that they don’t have screen time at Disney lol.
The great tip I found online was to give the kids wrapped “presents” every hour. I’m not saying big ticket gifts but dollar store stuff, snacks, etc. I would buy the stuff and wrap it, then use a sharpie to write the time they could open it. I would do a breakfast type snack around breakfast time (mini muffins) to hold them over until we stopped for breakfast. Fidget toys, travels games they could share, occasionally a sweet treat or candy I wouldn’t buy at home. I mean, the kids are going to eat snacks anyway, so this helped turn it into an activity as well. With the things being wrapped, it gave the kids some anticipation as well as giving my little one some motor skills activities lol.
We don’t sit down for meals - drive through is quick and less expensive. Plus - eating is the activity that helps pass the time. I’ve read with little ones that you should stop for fast food somewhere this a play place. You eat and let the kids run around and burn off some energy, then get their food to go when you’re done eating and they can eat while you drive.
We did print out the license plate game and played that on our trip.
We have a small garbage can in the car and made sure the car was emptied of trash everytime we stopped.
I also have a little bin in the car of “emergency supplies.” Wet wipes, tums, pepto, immodium, ibuprofen, spray deodorant, feminine hygiene products, Clorox wipes, and other misc things. We usually pack a roll of paper towels somewhere in the car for road trips as we had an incident once when a kid got car sick - not fun cleaning that up without supplies on the side of a highway.
Cookies sheets from the dollar store make excellent “lap trays” for coloring or playing when you need a flat surface. They store easily under a seat.
Definitely check Pinterest out for road trip tips with kids. There are a lot of good ideas which may or may not work for your kiddos.
Good luck and safe travels!