Issue 1. If it seems to stop coming out the dash vents and switches to the defrost its most likely a vacuum problem. Check the vacuum line from the intake to the vacuum reservoir (black plastic ball in the engine bay passengers side), then from the vacuum reservoir to the firewall. Also check the vacuum line from the hot water valve back to the firewall.
Issue 2. If your sure your leaking refrigerant, it could be leaking from any of the following: compressor, condenser, accumulator, evaporator, or lines. You can add a can of leak check (dye) and run the system for a day and then look for any signs of a leak.
2001 Ranger Edge 3.0 V6, 5 speed M/T
Limited Slip Differential, James Duff Traction Bars
Kumho 30x9.50 15 MT / Black 297 Series 15x7 Rims