We get by on solar off-grid for five months of the year (sunny half but no air conditioning required)
If we were in a park and on a meter instead of being charged for power as part of the fee, I would just use my own power and not draw so much on the shore power. I would control that by only plugging into shore power when I was down to 50% battery and solar had no hope of getting the batts back up in the cloudy day or whatever.
The exception is always air conditioning. For that, I would organize a separate plug- in for the a/c unit connected to the shore power pedestal on its own extension cord (not the Rv's actual shore power cord) and do everything else as though off-grid (including as we do, the microwave)