Well, we all survived. CD9 swallowed wrong on the way down and threw up, 2 hours out. We decided she wasn't actually sick (several kids had just gotten over a stomach bug, which she had somehow miraculously missed, but this seemed to be just car sickness, not "real") and kept going, after a stop to clean up a bit.
Then we somehow got lost for a little bit in Queens, but luckily we'd switched drivers by then (I drove most of the way down) and my husband was a lot less likely to panic than I am! I dug out my LI highway map and managed to navigate back to the Van Wyck so that we could get back on our directions, since my map didn't have enough local streets to get us all the way there otherwise.
We were about an hour late, but my husband was able to join them for the Mincha Minyan, we heard all the important speeches, saw all the important people... it was fun. I had no problem finding what to eat at the fancy smörgåsbord, but the kids had only "dessert" so we had to stop for pizza and French fries (the latter for my lactose intolerant but still picky kid) before we headed back north.
Wow, I have never seen so many Kosher restaurants in one place in my entire life. And I grew up 15-20 minutes away from there!
Trip back was pretty uneventful, except for the optical illusion truck traveling in front of us. It was practically invisible in the dark, except for the taillights, which really looked like three separate cars far off in the distance. My husband, who was driving, saw it and dismissed it as far away and ignored it. I woke up at that point, having dozed off for a bit, and having nothing better to do, was focusing on the lights for long enough to suddenly realize they stayed in sync with each other, and thus break the optical illusion in time to make him slow down well before we would have hit it. (We were going the speed limit, but the truck was driving a bit slower than that.) And even then, I was still unsure that it wasn't really three cars way far ahead until we pulled out and passed it... it was a good (if dangerous) optical illusion.
The kid who refused to go with us then went on an even longer car trip to Montreal in February, with a school-sponsored trip, with no complaints at all. Go figure.