If you're planning any type of travel with children, here are the best seven tips on traveling with children I can give you. My boys are 6 & 7 years old, my family lives 250 miles away so I'm offering my advice from experience.
First you'll need to pack some of their favorite quiet (very important!), small toys, books, blanket, teddy bear, pillow and pajamas. I still keep baby wipes in both pickups; you never know when you'll need to them. They are so versatile; from wiping hands & faces, to wiping up spills.
Secondly, be sure to pack enough clothes; I always pack two days extra and usually two more pairs of socks & underwear. If your youngling isn't out of diapers yet, packing is about the same, just make sure you have double the amount of diapers and wipes. Oh, don't forget a towel to lay the baby on and plastic zip lock baggies to put the soiled diaper in.
The third tip for traveling with children I have for you is to pack nutritious and non-messy snacks. Trail mix, There is something about traveling that makes children think they're starving! One word of advice; don't pack those small juice boxes; one squeeze and the juice is all over your child, the floor and their car seat!
Tip four is pack your child(s) medicine; prescription and over-the-counter. I always take children's Tylenol and Ibuprofen, a small first aid kit, Benadryl, small dosing cup, vapor rub, baby lotion, and a thermometer.
Tip number five for traveling with children is to try and keep their routine fairly normal; when mine still took naps, we would hit the road about an hour before their nap time, they'd nap for a couple hours and when they woke up, I'd stop for coffee and a snack for them, then in another hour, we were at Gramma's!
Another tip is to keep them entertained; pack some new toys, or better yet some toys they haven't played with in a while. New books are good or if they're old enough, story cd's with a book for them to follow along with.
Finally, the last tip I have for traveling with children is to make it an adventure. When we had 77mph sustained winds and took shelter in the basement, it was an adventure; we got eat out of cans, read books by candlelight, listen to the news via the wind up radio, they had a blast! When we go the 'all-clear', they didn't want to back upstairs!