Simple vacuum leak test is to warm up the engine then let it idle, 2.3l should idle at 800 with automatic, 700 with manual.
Now unplug the IAC valve it will close and idle will drop to about 500rpms, or engine may even stall, either is good and means no vacuum leak.
If idle stays high start pulling off vacuum hose from intake, one at a time, and plug intake port with your finger, if idle drops that hose has the leak, follow it.
'97 Ranger fuel pressure should be 35-42psi
Yes, you should have at least 30psi when engine and key are off, system should hold pressure for a few months, not minutes.
Fuel pump will run for 2 seconds each time the key is turn on, so cycle the key on then off then on again to get fuel pressure up and then turn key off and see if it holds pressure.
If not then either fuel pressure regulator is leaking, or the check valve in the fuel pump is bad.
Because you only get up to 30psi I would suspect the fuel pump, and since you smell gas in the rear of truck I would suspect a cracked hose fitting on the top of the tank.