I flushed & filled the coolant and put in the GM dealer (Suzuki part) thermostat. Hopefully that will fix the temperature problem.
I think the high idle is unrelated; it occurs mostly on its own without a temperature condition. It may have something to do with the broken bracket I just noticed:
There is a vacuum biscuit right on top of the engine that is connected by vacuum hoses to the EGR actuator among other things. It is mounted to a bracket that attaches to the intake manifold. The bracket cracked and the whole biscuit thing is now just suspended by the vacuum hoses, shaking around to beat the band.
I have to find a replacement bracket. Any sugestions where to look?