I would not call myself an expert but here are a few lessons learned from the Kentucky Bourbon Chase (200 miles with 9 runners race report here) and the Peak 2 Brew (236 miles with 12 runners race report here ).
1. Have a designated driver for each van. It’s not required by the races but it really helps to have a non-runner driver. They don’t have to do ALL the driving but even if they do some of it you will all be safer and happier
2. Plan, plan and plan again. We used a spread sheet to figure out when each runner was expected to start and finish each leg. We then adjusted the times at the end of each leg and calculated how far ahead or behind our projected time we were running. We did the adjustments manually on the go in the van. The sheet we used is here. If you want a working copy just ask!
3. Have a communication plan but don’t rely on it. We had planned to use one cell phone for each van and to have a text sent each time a runner finished their leg which included the runner’s name and the time they finished the leg. It worked well except in areas with limited cell phone coverage which turned out to be a good part of the course. Our default for major exchanges was to be there 30 minutes before we thought the runner would arrive.
4. Have a designated “stink” seat in the van. The one the hot sweaty runner who just finished their leg uses. Bring towels! We made the mistake of only having one per van- this year we will bring six and many of them may be making a one way trip. Put them on the seat to protect it and absorb the sweat!
5. Have a cooler and a shared water supply in each van. We set-up mini water stops for our runners along the course (this type of support is not allowed at all races).
6. Assume you will get NO sleep. You may get some but it will not be a lot. Do bring a mat and a light weight sleeping bag so you can sleep when and where you can. Ear plugs might be helpful too. If you sleep in a gym stay together if possible. It can be very difficult to round up your team in the dark!
7. Make time for real meals. When your van is “off” take the time to get a meal not a snack. You can survive 30 plus hours on Gatorade and granola bars but you will feel much better if you don’t have to.
8. Bring a foam roller. Running and then getting straight into the van makes everything get tighter as the day goes on. Getting out of the van whenever you can and walking around makes a big difference as well.
9. Set realistic time goals. You can probably easily run at your regular pace for the first one or two legs but it gets harder as the day goes on.
10. Have fun! Decorate your van, bring some noise makers and use them because running should be fun!
Racing and Traveling over 50. 
Sound advice I think. Though I’ve never tried it.