Shown below is a breakdown of the steering system on your ski. The only real problem you should have is with #25 in the picture, the nut where the cable passes through the rear of the hull. You can get this off 1 of 2 ways. You can remove the jet pump and get to it with a wrench. Removing the jet pump should take less than 30 minutes. The other way is a little trick I like to use. Take a 1" piece of PVC and heat the end with a torch, just enough that the pvc becomes soft. Then press the PVC pipe over the nut and it will mold itself to the shape of the nut, giving you a removal tool without having to take the jet pump off. If the cable is the only problem, you shouldn't have to replace much more than it. Just check the cable ends and make sure they are in good condition & replace any that are worn. You may want to just go ahead and replace the rubber parts of the seal where the cable passes through the hull just to be safe.
Below is the procedure for alignment of the steering system. Let me know if I can be of any other assistance.
Marine Mechanic
11 years experience working on outboards, inboards, sterndrives & pwcs