I believe that most manufacturers rate the camper pipework at 60psi (tho' I've been told that they usually pressure-test at 80psi).
I usually run our pressure at 55psi (with a Watts regulator, which I'd thoroughly recommend) - I ordered the 263A-LF from rvwaterfilterstore.com ).
We also have an Oxygenics shower head which I bought from Amazon last year and it's a LOT better than the factory shower head.
Just in-case anyone is interested, I bought the Watts 263A-LF pressure regulator (which has much better flow than any of those little cheap inline pressure regulators) from RVwaterfilterstore.com (great service), and attach it to the water inlet (with a 90deg elbow to reduce the pull on the inlet), though I am thinking about mounting it inside the basement.
2015 Rockwood Signature UltraLite 8281WS
2016 Ford F-250 Lariat CrewCab, 4x4, 6.2L V8