Would this be too much driving in one weekend for a 5 year old?

So my ex's parents wanted to take my daughters to Dutch Wonderland for their birthday, as my girls love it and talk about it all the time. It is abut 7 hours from us though. So they wanted me, my daughters, and my boyfriend to drive to their house in MD on a Friday, which is about 7 hours away with stopping and stuff, and stay the night there, and then just hang out on Saturday and then about 2:30 or so drive to Lancaster, PA (where Dutch Wonderland is), which is almost 2 hours from their house, and the park opens at 4pm and closes at 9pm. And then drive back to their house after that, and then we would have to leave late morning/early afternoon on Sunday and make our 7 hour drive. My daughters have met these grandparents twice so it would be nice to see them, but I just don't want to wear them out too much, do you think they would be fine?? They have gone on long car rides before.