Tricks for keeping restless passenger happy while towing?

We have done a lot of long distance driving towing the 5th wheel or recently in the Class C. and generally, I am the driver. Our Magellan GPS is Audio and announces we have been driving for 2/3 hours and time to take a rest/stop. Generally, we don't drive more than 300 miles per day which usually gets us to campground mid to late afternoon. Also, if my D.W is getting restless she will drive while I get to look at the scenery which I thoroughly enjoy.