Might have found it?
Hey Campers. Thanks much for the ideas. We picked up the 23H from Camping World this morning and brought it home. After it was safely parked in the driveway we did what we should have done in the first place - a thorough inspection of where the water might have come in.
There were a couple of places on the clearance lights that were suspect, and one of five didn't have any sealant on it at all. I pulled them all up and sealed underneath. Once they were screwed back down I added another line of silicone around the edges.
There were a few popped bubbles in the lap sealant that we refilled, but I doubt any of those were the problem because even though the tops were open, they were still sealed underneath.
I think what really bit us was where the curved part of the cap met the sidewalls. On the curved portion on both sides there were splits and gaps in the silicone, but on the driver's side where the curved part met the roof there was about a 1/8" gap with no sealant of any kind. It was exactly where it needed to be for that night of wind-driven rain.
Everywhere we looked, and everything we could get to is now caulked or sealed within an inch of its life, and it's what we should have done in the first place, rather than run to the dealer. It ain't rocket surgery...
As to the color of the water that drained out after the rain, it was clear. I don't think it stayed in there long enough to damage anything, and there is no musty smell at all inside. The mattress has dried and has been re-installed, so I think we're good to go. Having said that, we're due 3 days of rain beginning Sunday night, so we should have an idea before we go camping again as to whether or not this worked.
Thanks to everyone for their ideas and hints on where to look. It's a maze. Fingers crossed. Be safe, y'all.