Mystery solved. Leak found. (
Ross F-1 was right on.)
I was still getting water on the floor under that oil pan bolt. So, I removed the floor and that platform above the starter was loaded with water/anti-freeze.
But, it didn't seem to have come from that oil pan bolt as I had originally supposed. So, I wiped and blew everything off and started the engine and watched. In no time the water was accumulating there again but did not seem to be coming from that bolt. But, I could see an itsy bitsy trickle coming down the bell housing. So, up to the engine compartment I went searching again on the intake manifold for any leakage from the radiator hose I just replaced. Nothing. Then I saw this drip.
Coming from the end of the heater hose clamp bolt. In fact, you can see that the hose is almost pulled off of the heater pipe. That will have to be shoved back on, the clamp tightened, and we should be good to go for the road trip tomorrow..
Thanks for all of your help. It was, indeed, something from above. I just had to find it.