From the ac, what would cause cold water to leak from passenger dash at bottom to leak on the floor board enough to soak the carpet?

It is actually fairly common on Jeeps and the a/c is indeed your most likely culprit. The problem is that the drain tube from the a/c condensor only sticks through the firewall like an inch so when water drips out, it runs back in the hole in the firewall and down to your floor. The fix is fairly simple. A) go buy a hose about 6 inches long and 5/8 inside diameter and attach it to the existing one. B) rtv silicone the hole in the firewall.If that is not your problem, check windshield seal, door seal, and vents on hood!