[JRTJH]

I'd first ask if this is the first time you've used the trailer water supply on city water? If it has never worked, or you don't know if it works, then troubleshooting a possible issue (like the check valve in the city water inlet) would mean an entire water system inspection and function test. If it has worked in the past, then we can eliminate the potential for the factory or dealer to have changed or improperly installed a component.

If the system has worked in the past, this this is where I'd focus"

If you had a pressure regulator on your city water hose AND had it set for 50 PSI or less, you haven't damaged your system. The water pump provides 40-50 PSI and the city water provides that same or similar pressure. It is not accumulative, the max in the trailer water lines is going to be 50 PSI. Now, if you do not have a pressure regulator, depending on the city water pressure, THAT (not the water pump) may have overpressurized your plumbing and might have caused a problem.

The "water bursting from each faucet is normal as the system purges itself of air in the lines and the water heater fills with water, displacing air which will cause the "air spurts/splashes" to continue for quite some time.

My guess is that you've got a valve turned incorrectly in the convenience center.

I'd first start by disconnecting the city water, turning off the water pump, checking all the valves in the convenience center for proper setting. Then go inside the trailer, momentarily open and close every faucet to relieve pressure from the entire system. Don't forget to flush the toilet and turn on/off the outside shower. Then turn on the water pump and see if you have water at each faucet. You should. Next, turn off the pump, connect the city water (with a pressure regulator) and turn the faucet on. You should again have water at every faucet.