I have a GFI outlet on an external wall, next to an outside door. On
the inside wall of that door, I have a switch for the outside light,
and that switch is a little over 3' from the GFI outlet (at an angle).

How difficult would it be to install a second switch at this location
for the GFI outlet? Am I going to have to remove a portion of the
interior drywall to get to the existing wires, or is there an easier
way?

For anyone that's kept up with my earlier posts, this is NOT the same
GFI outlet that the contractor poured gasoline into! LOL This one is
on the other side of the house.