Depending on how good or bad the campground 30 amp is (some will drop the voltage with any kind of current draw), we'll put the frig and water heater on propane. We also don't run the microwave and any other high-draw appliance (such as hair dryers, the coffee maker, etc.) at the same time. I have a hard-wired Progressive Industries EMS (electrical management system) installed that will take the rig off-line before the voltage drops to a point that it will damage appliances (which it has done several times in older, out-of-the-way parks).
Rob