Could it be that the car didn't originally come with cruise control, and she
was in the middle of putting it in or having it installed? It seems odd to
me that there would be a blank spot for the cruise control fuse. Which
engine is in your Regal?

When I owned a 1989 Chevy Caprice, the problem was the Multi-function
lever.  I replaced the lever with levers from the junk yard and some of
them would work. I bought a new multi-function lever on ebay and had no
more problems.  I would not try running the new wiring "inside" the
steering column because on that car everything was packed tight in the
column and the string broke.

   Hey George, don't think you are dreaming.  GM must've had some servos
and short speedo chains left over, because they used servos with 2 chains to
reach the speedo from the tranny.  The servo did nothing but serve as a
coupling for the 2 chains.  The REAL cruise was an electronic unit that
picked up speed via a pulse generator rather than thru the servo.
   Quite mind boggling to someone facing it for the 1st time.  Just imagine
the poor soul who had a servo to freeze & break a short chain or 2.  He then
bypassed the servo with one long chain just so the speedo would work.  And
by golly, the cruise still worked!!!  Happened to me--hope that means it
happens to the best of "us".  Luck to you.  s