I have one of the pressurized cleaning bottles that couples just as the keg does. And don't assume that because your system is limited use it needs cleaned less. Once that beer enters the lines and faucet, the bacteria does the same thing it does in a system that is drawn every minute. The flavor of your beer depends on you maintaining the lines at least once a month (I do mine weekly).
For a temperature gauge I suggest a GOOD freezer/fridge thermometer to monitor the cabinet temperature. The Wal-Mart ones are not good ones IMHO.
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