Thanks for the extensive reply & suggestions.

We've had this car for 20+(?) years so I'm familiar with its nuances. But as it has been a garage queen for about 5 years (doesn't get driven much) it's hard to make a concrete statement about coolant level. The white smoke / steam was a new behavior immediately post-inspection. While running a no-pressure cooling system is not great, I've done that for many (10?) years with little issue.

I immediately assumed a head gasket leak, but the lack of apparent spark plug or piston top "cleaning" makes me question that. I was hoping that someone had seen this specific behavior before and could provide insight.

As well as having neither time nor money to throw parts at problems, I like to get fixes right so I'll have to try some more diagnosis and maybe spend $$$ on a leakdown gauge set before proceeding. I want to fix this problem before buying a new muffler for the now rusted-out new muffler to pass the now overdue state inspection. (Sometimes I think I should simplify my life, but what fun would that be?)

Thanks again for taking the time to provide those extensive suggestions.