That is pretty much correct. I much like youself purchased a keezer from craiglist. Mine however had already been converted to a kegerator. Best $25 I ever spent, considering it came with a CO2 tank, all the lines, and a single tower. However, the guy I got it from did not homebrew. He had purchased it from someone else who had put in a thermostat like you are wanting. He said when he went to adjust it, because it was starting to freeze, the thermostat poped and smoked. So he quite using it. The connections were not done correctly. He did the right thing because it was a firehazard. However upon rewiring the freezer, i figured he blew the thermostat. It was around $50 for a new thermostat like you are wanting. On top of that the wiring to put it in place, and the experts at the appliance parts place were not certain on what one it would need to get the freezer to run say 40-55. Save yourself the time and trouble and just spend the extra $15-$20, its well worth the time and hassle.