So, by now you should be able to figure out that we travel a lot with the kids. Most of the traveling is for moves, but some of it is for fun/visiting family. Here is how I plan out our trips.
Both of my girls are given their own packing list. In the beginning they got pictures drawn beside the item so they could figure it out. I then go through their stuff they picked out to make sure they got enough of everything. Normally they have, but every now and then we have to add something.
For the car, this is the time consuming part. All 3 of my kids have a travel backpack. It has a little lap desk in it that will hold papers, markers (washable only), dry erase marker and pencils (mechanical so they don't have to sharpen). They also have print offs, toys, video games and books in their bags (see below for examples).
PRINT OFFS: I normally print off car bingo, the license plate game, mazes and whatever else that that I can find to keep them busy. If you put them in a page protector, they can use a dry erase marker on them over and over again.
TOYS: I also try to add a few small toys for them to play with and explorer while we are going. Right now my kids like Squinkies, so they have a large assortment of them. We also have small cars, kids meal toys, and anything else that I can find that I think they might like.
BOOKS: This is a little bit harder with my 5 yr old, but they all normally have a book to read in their bag. I let them all pick something out at the bookstore, and then it's put away for the trip. They can all share during the trip so they have more to read. When my 5 yr old was younger, he loved the I Spy books (level 1 readers) (this is just a link to one of the many we own). It has a picture of what the child needs to look for so there is no reading involved.
Video Games: My kids do play them and have to share the games between each other. They are charged before we leave, and aren't charged again until we stop for the night. If they die, they have to find something else to do. They are not allowed to play with sound on unless they have their headphones on.
We do have a dvd player in our van. It is a lifesaver at times, and the kids all take turns picking out movies. Normally I make them listen to it on headphones. They do sell splitters to connect more headphones to them, and extensions so the headphones will reach the backseat. There are rare times though where I hook the sound up to our van so they can hear the movie better and so I know what they are watch. I do pack all of the dvds before hand, so I do limit what they are allowed to watch.
Snacks are an important part of traveling I know. We pack fruit snacks, trail mix (m&m's, cereal w/marshmallows, Goldfish crackers, and pretzels), string cheese (in cooler), and sometimes veggies. If I'm traveling alone with the kids, we bring sandwich fixings with us (tortillas, sliced cheese, and sandwich meat) which my kids will make while I'm driving. We only drink water while we are in the van too (everyone has their own cups so we don't share germs). It helps to create less stops and if it spills, it isn't a big deal. We do stop about every 2-3 hours to fill up on gas. The kids stay inside while I do that. Once I'm done getting gas, we drive up to the building and we all hop out to use the bathroom quick so we can get back on the road. Even if they don't have to go, the rule is that they still have to try.
While it does seem hard to travel with kids either alone or with your spouse, it's not that bad once you get use to it. It also gets much easier as they get bigger and you have less to pack.