Unless your starter is on the way out, or you must have heat blowing into the cabin, you should definitely turn off the engine any time you stop off the road. There’s simply no reason to waste fuel by running the engine in a regular passenger vehicle.

Your stopping schedule is wise. I’d suggest every second stop be a longer one so everyone can get out and away from the road. It really helps all, especially the driver, to stay fresh.

Start early and stop early. Dusk is a particularly bad time to be on the road with significant traffic. Everyone’s tired and rushing to get home, and their eyes are adjusted to bright workplaces.

Schedule and route to stay away from large urban areas during rush hours, if possible.

Get fuel before entering an urban area if you’re on the low side. Cost will likely be lower, and getting off and back onto the highway will be easier. Try to avoid going below a quarter tank and be aware of any stretches where fuel availability might be limited.

Avoid coffee, “energy” drinks, and the like as an aid to keep driving. If that’s needed, it’s past time to stop, perhaps for the day.

If it’s a multi-day drive, avoid alcohol beyond one drink when the day is done.

Have fun. Help everyone in the car with you to have fun. Be safe and help everyone else on the road to be safe.

Tires, brakes, lights, battery, oil, and coolant are the most important vehicle components to check. Also tires. And don’t forget the tires.

(I grew up in the wayback of a Dodge wagon on the interstate and have taken many drives of several hundred to a few thousand miles both alone and with a co-driver. I still love doing it.)