The fuel pressure regulator is a relief type not pressure reducing like one found on an air compressor line. The relief type dumps excess fuel to the tank, this the sound you were hearing when the fuel pump was running.

Hitting the intake won't do anything to solve the pump run problem, you will need to look at the relay that controls the fuel pump / wiring. This should be one of the years that had bio degradable wire correct?

An engine will crank even if fuel pressure is lost.

As an added test, though I doubt this is your problem, pull the engine oil dip stick and smell for fuel / vastly overfilled. I've seen vacuum referenced fuel pressure regulators fail / fill cylinders with fuel and hydralock the engine to the point it won't crank. If the engine is left to sit a while fuel will seep past the piston rings allowing it to crank.