I was told the plumbing was designed for 85 psi max as a test but normal use should never be more than 50 - 55psi. I strongly suggest using a pressure regulator. I've been to parks with big signs stating "Water pressure high, we are NOT responsible for damage. Regulators available for sale at front desk".
I have a gauge before and after my regulator and I've seen pressure as high as 90 psi at the park faucet.