Well, we're back!
The drive there was easier than the drive home! We stopped 3 times (an hour for each meal). He did pretty well. I only had to climb into the back seat once on the way. On the way back, I was in the back twice, and DH was in the back twice.
We figured out that he is now teething!
His sister cut her first tooth at 4 months, so I guess it's his turn. He's been SO fussy lately. Oh well... at least we're home now!
Thanks for all the advise!