I do have the right caps on the car, so that probably isn't the issue.

With the thermostat out, the car ran 60 miles between 170 and 180. Going to call that good enough for this weekend and so I'm going to make the drive south and then try fully solving this when I get back.

I'll do a nut and bolt check tomorrow night and for now, just trying to decide now which tools should go in a bag just in case :-)