I own a 1989 2 door Cherokee and I've been struggling to find a receiver that bolts up. The napa kit says it installs on the XJ without drilling. for the 2 door that is not the case. Where can I go to find a kit? and where specifically can I find the differences in the bodies so I don't encounter future problems like this?

Never heard of it. I part Cherokees out and have interchanged hitches with no problem.

Do you know exactly why the NAPA hitch won't fit a 2-door?

Right now i can't think of any reason why a hitch would only fit a 4-door and not a 2-door. Maybe someone here smarter than me can think of a reason.

Does your Jeep have a fuel tank skid plate?

XJ Class IV hitches utilize the factory holes on the bottom of the frame rails near the bumper.
Some of the holes on the right rail are used to mount the tail pipe hanger via an internal nut strip inside the frame rail.
Depending on the amount of rust or if the hanger bolts break, the right rail nut strip may or may not be usable for the hitch installation.

If the Jeep doesn't have a factory skid plate, the left rail might not have a factory installed nut strip. If its not there, not a problem.

Typically for aftermarket hitch installation, large carriage bolts with a rectangular washers are fished into the frame rail opening near the bumper and into the factory holes.
Then nuts instead of bolts are used to secure the hitch.

The bodies for the 2 door and 4 door xj's are exactly the same except for the number of doors. A hitch that fits on a 4 door will fit on a 2 door and vice versa.