Buy a $10 grinder from Harbor Freight. Buy a $100 wire feed welder from Harbor Freight. Buy a $20 door/hood/fender from any junk yard, and learn.

The cutting out part is really, really easy. It may be a slight challange to get inside the rocker, but not too tough.

If you don't feel comfortable learning to weld on your own, use rivets like already suggested.

 

I found some rocker repair panels at Noram auto body parts for $30 plus shipping. Not a bad price but I'm still looking for the inner panel that is also toast.

My question is this, Their site lists the part as : "Jeep XJ Series Cherokee & Wagoneer 86-95 Slip-on Rocker Panel 4 Door" I thought the body parts were interchangeable from '84 to '01. Do you think this part will work on my '00?

 

Since I've never bought one I can't be 100% sure, but if they say it won't, it probably won't. You may be able to call them and find out if they don't fit, and why they don't.