Here's a photo of my 1994 Ranger. 1 owner, 78,000 mi, 4.0 v6, 5 speed. Runs and drives like a new truck other than needing a valve cover gasket.

 

Nice looking Ranger

I also have a '94, extra cab, 4.0l, 5 speed, but 4x4, over 300,000 now, so you got lots of miles left on that one

Use the cork gaskets and make sure valve covers are straight(flat not warped) before reinstalling, the bolt holes in the thin metal valve covers get deformed when tightening, so pound those flat again.
Common leak point is the rear lower side since that is where the oil pools and sits because of the tilt of the engine.

Cork gaskets swell over time which is why I prefer them over rubber, but rubber is better if you will be removing the valve covers regularly because they can be reused unlike cork which will tended to harden and then break when removed.

And do not over torque valve cover bolts, it will deform the metal causing leaks.
Valve cover area has no pressure inside, just gravity, and with engine running it actually has negative pressure inside because of PCV(positive crankcase ventilation) Valve system, so easy does it on the bolts.
And check PCV Valve and hose.

Oh, and watch the firing order on the coil when you reinstall it, I mix that up on these V6s all the time, lol
3 4
2 6
1 5

3.0l has same thing

 

I have to vote against using cork gaskets. I've never had good luck with them. I use the rubber ones or silicone ones that are sometimes blue.