I've got a 98 ranger with the same problem, only it's really bad.  I
can usually get it, but it takes close to a minute more often than
not.  2 other people have tried for minutes on end and failed, seems
I've developed the knack.  I had ford cut me a new key from the vin,
and it was worse than the well-used copy that came with the used
truck.  They told me that it was common on these trucks, and tried to
sell me new locks, which I didn't care to pay for.  The locksmith
thing is a good idea, I'd be curious to hear how the new key works if
you take this route.

I've been noticing that the locks on my 2001 Ranger XLT are becoming
harder and harder to unlock with the key. I have to wiggle and jiggle
it to finally get it to release the lock. Anything I could do, short
of taking the door apart?
thanks.