We have experienced water pressure at parks from 10-80 psi. One of the advantages of having a pressure regulator (at least one with a gauge) is that you know, when the water is dribbling out, that the problem is with the campground water pressure and not your water system. We have never set our gauge above 60 psi when hooked to the tt, as that is what the manufacturer states the max pressure should be, though we have found water pressure that was higher.
We have also had a white hose freeze overnight in 25F. If you have no water in your on board tank, you have to wait until it defrosts for the morning coffee. It is easier to disconnect and drain it at night, than to try to thaw it in the morning. Don't ask how I know.
Check to see if your on board water tank is insulated. If it isn't, fill it more than half full, but not all the way. Less water will freeze faster. Experience is an excellent teacher.