Site running is all about maintenance and crisis management.
Checking fuel levels for the generator.
Perimeter walking the site's fences and repairing any damage, closing any unauthorised gaps.
Keeping the bins emptied and the site generally tidy.
Ensuring the heaters are turned on when appropriate and off again afterwards, leaving a heater turned on when not needed costs significant amounts of gas.
Walking any power lines to ensure no unauthorised alterations have been made (living vehicle users have a habit of tapping into power lines).
Communicate with security on any concerns they may have identified.
Occasionally there will be some unpleasant moments, asking people to move cars, tents etc. isn't a nice thing to have to do and they don't always like being asked, but as long as you can give a valid reason why, they will normally comply.
General Housekeeping duties.