I finally got around to pulling the thermostat and installing the new one this morning. It wasn't too difficult once I figured out the fan removal. I don't think there is any doubt that the thermostat was the culprit now:
It was a bear to get out since the thermsostat was totally deformed inside the housing. Nothin a set of vice grips didn't fix!
I'll go grab some more coolant today and reinstall the battery. Hopefully everything works!
Thanks again to all of you for the help.