So this is probably a dumb question but I'm asking anyways. Can I add cruise control to my XJ? How much is involved? Is it worth the hassle?

 

'99 like your profile says?
Piece of cake. Did it to my '00.
IMO best to find a donor Jeep and pull the parts yourself instead of trying to buy one off Ebay.
Or worse yet try to piece one together off Ebay.
Research it but a couple tips.
The switches on the steering wheel need to be from a '99 to '01. Assuming you have a '99 that is.
To the best of my knowledge the rest of the parts can be from any '97 to '01.
When you remove the steering wheel to take the clockspring try to make sure the wheels are straight.
A clockspring has this big long ribbon in it. Needs to be centered. Why you want the wheels straight.
When you pull it secure the 2 halves so they don't rotate on each other and become uncentered.
If you can't get the wheels straight or if the 2 halves rotate it is not the end of the world.
There is a recentering procedure so...
Steering wheel puller can be rented from most auto parts store.
Cause you will need one.