We drive from MA to WDW every time - trip time is about 23 hours straight and I've always driven it in 1 stretch. It's long but we leave around supper time and get to WDW around supper time the next day, eat at DTD, and then bed early so we're ready to go for rope drop the next morning. Maybe because of the fact that we've taken the kids on road trips consistently, they travel well with minimal issues.
To eat up time (pun intended) we leave the house around 5pm, stop and pick up something for dinner - pizza, grinders, Boston Market, whatever. Food they generally only get once in a blue moon as I generally cook 7 days a week. They eat at the beginning of the trip. Doesn't take up a lot of time but still keeps them busy. Then we usually pop in a dvd - when they were younger they watched the same thing, as they've gotten older we've learned to bring 2 of everything - they each have a dvd player, IPod, DS, and ear buds. They have the option of watching/doing the same thing but also the ability to do their own thing if wanted. They fall asleep at that point and we drive through the night. Sometime around 7-8am we stop for breakfast. And by that I mean STOP and sit down somewhere and eat breakfast - Usually somewhere that has a kiddie play spot - McDonalds. Kids get a chance to blow off some steam. Then we make the last stretch and get to hotel & check in. Bathroom stops whenever needed but try to make them around gas fill and coffee stops. I drive 99% of the time but that's only because I drive distance better.
What to pack for the actual trip -
- kids get a backpack to fill with whatever they think they would like to use during the trip - DS, phones, I-pod, Nook/Kindle, have to fit in the bag - not those items plus. I pack a couple extra dvd's of my choosing just to make sure there is something mutual. Summer reading book, drawing items, etc. whatever that child is into. I do make recommendations.
- snacks - again I try to pack things that they don't normally get around home as well as favorites. Goldfish, PB crackers, gummy snacks, juice boxes, those cheese and cracker stick things, pretzels, fruit.
- a plastic coffee ground container (empty) - great to have just in case of a car sick moment. Nice to have a solid container vs. plastic bags that the child can have and the nice cover to ward off those vomit aroma's. If you don't use the container, it's awesome to use at the hotel to throw small things into - change, cards, anything the kids pick up (or this scrapbooking momma).
- favorite pillow, lap blanket - we bring these as we tend to travel during the fall season and it's chillier up north here. Also the kids tend to sleep better when they have their own familiar items. When they were younger we brought their security item - DS was a pooh bear, DD was a teddy bear blanket (bear bear).
- trash bag for trash - snack containers, coffee cups, etc. I usually just bring a bunch of those bags you get at the grocery store/
Walmart/etc. and throw them out as I stop for gas, coffee, potty breaks. No cost to me to get the bags and easy to tie & toss at rest stops.
While I know we have a lot of room with the car vs. 1 bag with flying I still try to only pack what we need vs. the whole house. Usually my daughter will get a "dust collector" AKA stuffed animal(s) at WDW so we let mousekeeping play with the new animals - flamingo & pooh were caught watching tv several times. Inside the car has to be "livable" and not overly crowded for the people IN the car. I put everything we don't need for several hours in the trunk.
Our trips have been 10-14 days long so I plan on a pool/laundry day - throw in a load, sit by the pool while kids swim, change to dryer, sit by the pool. I just use the pull suitcase to transport clothes back & forth to laundry facilities - no extra baggage. I plan on bringing the laundry soap pods and fabric conditioner sheets - in the past I brought the almost empty bottle of laundry detergent (pre-pods) and just finished it and threw the container away.
I bring beach towels from home for the pool as the pool facilities don't have extra towels plus the colorful towels stand out in the pool area so we don't have to search for "our" area.
Ziplock bags quart and gallon size. As I mentioned earlier I scrapbook so I always have a couple bags in the park bag - backpack or camera bag. Confetti, maps, etc. that I see in the park end up being collected for later usage. But there are a lot of other uses for ziplocks.
I try to hit a grocery store on the way to the hotel and buy local fresh produce. This way we have healthy snacks IN the hotel room during our trip. I bring a case of water as we are a HUGE water family vs. soda/juice, granola bars, individual packages of nuts/raisins - these are items I pack in our park bag as well. Not a lot but enough to hit those waiting in line and wanna munch moments. If we go to a buffet breakfast there is usually fresh whole fruit and we try to grab a couple oranges/apples to snack on later on.
For your personal care items that you bring from home - I try to pack the nearly empty items - shampoo bottle, conditioner, etc. so I finish the product while there and toss the container. A lot of mail freebies are travel size too so I make sure to sign up for the ones I know we would use and pack that stuff for traveling. This way I have less stuff coming home vs. going and more room for souveniers.