Will do. At least it's not over-heating.

However....this weekend, when travelling down hill on a cool, foggy morning, for an extended time, (10 minutes), my temp gage dropped to about 120 degrees.

I've previously verified dash gage readings vs. a digital thermometer.

Temp came right back up as soon as the engine was loaded. Guess I now need to check operation of my thermostat...

Sounds like your thermostat could be sticking. If it sticks in a fixed position, say half open, it can cause overcooling (downhill no throttle) and overheating under heavy loads. Its easy to check without dismantling to much and they are not expensive.

Chas