Without a doubt, I'd take 2 cars. For a hundred reasons. It will be impossible to time stops convenient for all of you. In one car, you stop for the girls to use the bathroom, they will wake up a sleeping baby. In your own car, even if you pull over with them, you won't have as much noise. That goes for drive time as well. 4 and 5 year olds just don't sleep as much in the car as parents would like them to. They will play, sing, and fight, all of which will keep the baby from sleeping when you want him to. Like dogs in the neighborhood, one starts yelling, they all chime in!

It's going to be hard, but that would not stop me if the trip were important to me. I think I'd try to get him using a sippy cup or bottle or sport bottle w/straw -something else he can drink from besides me (if you are breastfeeding). It will help "get him by" for a little while until you can stop. Mine would drink from a straw at 6 mos, they really pick it up quick. Travel as much during sleeping times as possible. Stash some interesting new toys to take out as needed, things he can explore for the first time. Expect to set next to him a lot, most of the time he is awake. Keep diapers and wipes in the side pocket of the door, or something, where you can get to them very quickly. Take some plastic bags to dispose of them. During big driving days, dress him in layers to help keep him as comfortable as possible in heat or air conditioning. If you don't have them, get shades for the windows. When we travel, the sun always seems to be in the wrong place for the baby to go to sleep or street or headlights wake them up just as they are almost asleep! Very frustrating, so shade them well. Keep an old blanket with you, so if you stop at a park or rest area (or any grassy spot) you can let him stretch. When we've travelled with our kids that young, nothing settled them down better than a chance to be on the back or tummy, change them in the fresh air to "air out" that tired bottom.

And take a really big bottle of Excedrin -you'll probably need it LOL!

Take two cars.

The baby will NOT be OK for that long - you will have to make numerous stops, depending on the baby! When my DD was about that age, my husband & I took a long car trip. We ended up with one of us driving & one of us sitting the the back seat with her. That kept her contented & let us make better time. I also remember her getting carsick, so make sure you keep a few towels inside the car & changes of clothes where you can get to them easily. Pack what you absolutely have to have & buy whatever else you need when you get there. You'll probably have to do laundry at least a couple of times, so you might throw a box of laundry detergent in the trunk of your car.

Warning - maybe YOUR husband is a big boy, but when we took our trip with our infant, he was just as bad. He didn't pack what HE needed (he thought I was going to do it - like I had time? duh!), so make sure your husband IS taking care of his own packing.

Have a great trip!

We've done long 9 hour trips with a 6 mo old, and they were hard. two cars would be a lot better, because, well, it's a long time to be stuck with the same people. it would be nice to have the option to split the older children up, for example, or let the sleeping baby ride away from the rest of the gang, as a previous poster suggested. besides that, once you get to where you're going, you'll have a lot more freedom. We have friends who have vacationed with family and only rented one car. it was a disaster, because everyone wanted to do something different.

Prepare to stop at least every few hours. Don't have a rigid schedule- it'll just make everyone irritable and frankly, there's almost no chance you'll be able to stick to it with that many people.

Bring lots of car friendly snacks- a cooler with juice boxes, grapes, lunchables... that sort of thing. Try to get separate walkmans for the kids, and rechargable batteries. know anyone with a tv-vcr that can work in the car? we borrowed one for our last 15 hr drive to Utah and it was HEAVENLY. I'd highly, highly recommend it. kept our 3 yr old entertained for hours.

I bet you'll have a great time. :)
-sara

Take 2 cars for sure. There is no way you will get any agreement on who wants to go where and when etc with a van full of 7 people. Stop very frequently. Bring disposable everything. Make sure your husband knows that he will have to share some of the child care while on vacation. Bring only what you need for the car trip. You will be able to get whatever you need when you get there. You are not visiting any 3rd world countries.

Plan some overnight stops and make sure you let the kids have some time to swim, and play during those stops. Game Boys, TV/VCR combos, walkmen (??), coloring books will all make for an easier ride.

Have fun.

Mommabear

2 cars. I agree with the postings. Stephanie's suggestions were good about the shades etc. If you know he travels well, that's a good start but be prepared for the worst and it probably won't happen. Have the essentials-wipes, snacks, drinks and most importantly, something he is comfortable and familar with like his favorite toys and blankets. Maybe he would like music playing as well. The other kids are at an age where they are too self-centered (no offense, mine is that age) to be concerned about an infant's needs. You will be MUCH happier in your own car.

Heck you'll need two cars if you're bringing any luggage. Also, be sure to get a pair of those two-way radios so you can communicate with the other car easily. Unless yoou both have cell phones.

Trish

Great tips!!!

Just remember to have fun and enjoy this time. They grow up so fast....

Now on to the reality of it all. I am an army brat...traveled overseas a lot when I was just a baby. Then I married military and I was the traveling mom...lol. 9 hour plane rides with infants....endless travel in cars....so the tips that everyone suggested are great. I would say take two cars. You may very well enjoy the 4-5 yr old girls NOW...but by the end of the trip...you may think otherwise. Taking two cars will allow you and your husband some time away from kids that may or may not drive you nuts. Also think of it as a time for you and your husband to spend some great time talking and sharing the ride.
Your lil one will probably sleep most of the time. If not, toys that attach to his car seat are a great idea. And yes, bring that blanket and let him stretch, roll around on his belly and you can work him out as well. Have him lay on his back while you gently push his legs to his chest and then straight again. Like a mini work out for baby...again the fresh air and the exercise will tire him out and off to sleep he goes. =) One last thing to remember....medication. It is always at this time that they find some bug to catch or a tooth decides to break through. So be prepared with the childrens cold medicine, tylenol and teething gel. If you bring the cooler....a cold teether is great entertainment and keeps him cool too.

The less stressed you are.....the better baby will travel. So be prepared and relax...it's supposed to be fun and enjoyable.

But definately have options available so that you are not "stuck" in a situation that you, your hubby or baby can't get out of. TAKE TWO CARS. LOL

We took a 17 hour driving trip when my oldest daughter was 5 and the youngest was just 3 weeks. We didn't leave until around 8pm. My oldest fell asleep shortly after we left and slept most of the way. Since the baby was sleeping through the night by that time she slept most of the way too. This might be an option for you if you don't mind driving at night. Another plus to this is, the traffic at that time of night was great!

May is pretty enjoyable in Texas. It's not quite a hundred degrees yet and not as humid. But, I'm from Texas so I'm used to the heat and humidity. Make sure you take sunscreen and a hat for your baby. And lots of water.

And just say no to jeans and tight fitting clothes. I stop wearing jeans in April.

And six month olds are a joy to travel with. They can't say "are we there yet?" a hundred a fifty times an hour!