Ropdoc
Is this a problem that exists at you current campground. Some states require campgrounds to have flow restrictors in the faucet. When a flow restrictor is used you cannot screw the hose on with the standard screen in the hose fitting. The screen will not allow the flow restrictor to operate. When a flow restrictor is in a faucet you will never be able to get the pressure that you need. Pressure regulators can and do go bad so your problem could be a stopped up regulator. Try putting water in your fresh water tank and see what your pressure is like with your water pump running. If it has good pressure then it is not in your plumbing.