Traveling tip for infant

I have taken 1 hr road trips (one way) to the dr with LO before but am looking into doing  a 3 hour drive to see family next weekend. LO is 9 weeks and typically does good in a car. She likes to look out the window and generally will fall asleep. Any advice for traveling a farther distance? She's getting to the stage where she gets bored and wants to lay down and kick her legs/ stretch out. I'm just worried she will get bored. The longest she has slept during the day has only been an hour at a time. She eats every 2 1/2-3 hours during the day as well. If needed I will stop along the way (I plan on at least one stop) but was just curious to hear other pieces of advice to make it go as smooth and as easy as possible.