I'm not a kegger but it seems the beer would store better if the keg was purged of oxygen and a moderate amount of CO2 pressure was kept on the beer to slow the eventual oxidation.
Moderate changes in temperature won't affect the quality of the beer over the short term. You may need to put a Best By label on the kegs based on the style. Dark beers will keep longer than light beers. Sours or Brett beers probably the longest of all the styles.