An update, good news first:
There doesn't appear to be any coolant loss yet, but I haven't had much time to track it very well. It does run nice and cool as it should since I added coolant. Oil and coolant still don't appear contaminated with each other.

The bad signs:
The exhaust smells sweet. There is very little smoke, but that which I could see was light in color and not the usual black sooty stuff. I ran the engine up to temperature with the cap off to look for bubbles, and found them when revving the engine (see pic below). I guess it is possible that these are innocuous air bubbles escaping as the system burps itself from being run low?

I know that head gasket problems are really rare on this engine, and I'll continue to watch the temp and coolant level and hope that Marshall is correct (you haven't steered me wrong yet). Guess I'll order an oil analysis for definite confirmation yea or nay.

Thanks for all the help,
Tom