Go to a big box store and ask for a $40 whole house Watts water pressure regulator. No need for a gauge, other then for looks, and it's just one more thing to get plugged with debris.
I took that whole house unit, and then worked it into a whole house water filter with adapters to two 10 foot white hoses to use at the parks. Works like a champ and has never plugged on me. Prior to this setup I had one of those cute little regulators with the gauge and house ends. That lasted for about 6 months of snow birding until the unit plugged and stopped regulating the pressure. I would never recommend that unit to anyone.
Highest water pressure that was noted at a park was 160psi. I would hate to have one of those smaller regulators at that park.