As 98liftedranger stated, check for missing plugs along the lower end of the firewall.
A few other areas to check would be:
The cowl drains. These can get plugged from debris such as leaves etc. You can verify this using a garden hose and running water into the cowl. The water should exit just ahead of the door opening from underneath. If there plugged, use a straightened coat hanger and run it up the drain from the underside while running water to flush the debris out.
Kick panel screws at the bottom of the door openings.
Opening around the windshield.
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