I used to attend my college homecoming every year, stay until late in the evening and drive home (about 70 miles, mostly on the highway). There were a few years when I would get home and realize I had no recollection of driving on the highway - like, how did I get home?! I was a lot younger then and not afraid to drive home late at night, and I never drank before I made the trip home. Now I either come back earlier in the evening or stay the night and come home in the morning.

When I worked midnights, there were a lot of evenings when I would get in the car at 10 PM to go to work, start the car and the radio would come on at a super-high volume from my trip home in the morning. I don't miss those mornings!

Can you take a break during your trips with your granddaughters? Couple of hours, and then you stop for even a short break? Or take turns driving, maybe? Hope you figure it out so you can enjoy trips with your grandchildren.