Tricks for keeping restless passenger happy while towing?

I'm not the one that gets "antsy", but the daughters do. I drive about half the time and DH drives the other - usually the first half. I do the backing up with him directing. We stop at rest areas, every 2 hrs or for lunch. We will all get out and stretch, run, walk or usually race to "something". It gets the blood pumping.

We try to limit our trip to 6-7 hours on the first day and hopefully less than 4 hours, the second or subsequent days. If I didn't do some driving, I would be having a "difficult" time, too.