You are not crazy. Seven hours is really easy and doable with little ones. We have family a bit farther than that and we have been doing it about once a month since our youngest was really little. My oldest suffered from terrible motion sickness so done that one too. Ill share a few tips that we have found that work well. Don't stop so much. We find that it really does not make the trip easier.....just longer. On a 8-12 hour trip we stop once or twice. Even as toddlers that worked better. With 7 months your little guy should have the potty thing down pretty good. Remember little boys are easy to potty...any safe pull over and a tire to aim at works. If he is not at 100%, put a pull up over his underwear. Not as an excuse to not go potty, but insurance to prevent cleaning a car seat cover just in case. If you do want to make a few stops...make them work for you. Stop at a fast food place with a safe indoor play area; adults eat while the kids play and take the kids food to eat in the car. Another good trick is to look ahead and find a nice rest stop coming up....plenty on 95. Grab fast food and take it with you and have a picnic at the rest stop so the kids can run a bit. Again if they just want to run...it's ok....they can eat in the car.
The motion sickness is a bit more of an issue. DS1 would throw up if we were in the car more than an hour when he was a young child. We did find however, that looking straight ahead, such as at a movie, did not bother him. Looking off to the sides did. Also playing an electronic game would also not bother him. Looking at books or drawing would. Check some of these out on a short trip and see. When we was little, drs would not approve motion sick medicine for a young child. Check with doctor to see if anything is now available. Also, if he was asleep, he was not sick. Perhaps start out really early, in the dark and he might sleep for a few hours. Take flat ginger-ale, or sprite or sweet tea in a sippy cup but dont let him chug it. Don't let his stomach get too empty. Oyster crackers are wonderful and not too messy but any sort of simple, not too sweet cracker or cookie is ok. Dry cereal is also good. Take clean up supplies, just in case and have a change of clothe accessible. Lots of fun activities to keep them happy in the car is great too. If you find it does not bother him, your ipad will be your best friend. Down load movies, toddler apps etc. Other good ideas are silly putty, stickers, pipe cleaners, books for you to read aloud to them, color wonder sets if they don't bother him. Sing, talk, and play simply fun games such as guess what animal I am. The best toy will be you. If possible, you might even want to sit in the back part of the trip. And.....dont forget car seat safety is number one always! Neven compromise for a whinny child. Keep them in the safest seat possible....rear facing for the little one and for sure some type of 5 point harness for the little boy. Sometimes people want to upgrade to the next level seats for a trip when that is really when you need to be most concerned about safety and comfort! Have a good trip!!!!!