Hi,
There are a few kits on the market you may want to look at, they are as follows:

Du-BroProducts.com

Greatplanes.com

SullivanProducts.com (recommended)

After using kits for a while I found making my own was simpler and even better.

All you need is a roll of u-control cable and some small diameter copper or brass tubing for the "crimps" about the size of a ball point refill tube.

Slide a crimp onto a cable, thread the cable through the servo arm and back through the crimp, slide the crimp close to the arm to about a half inch and carefully crimp with a pare of side-cutters (twice) and cut off the extra cable.

I usually hook up the rudder first and adjust cable tension at the rudder servo with the final crimps.

There are factory "horns" you can buy for the rudder or you can just use two control surface "control horns" back to back.

You can also install a pull-pull tail wheel at the same time, just hook up the wheel cables from the double ended control arm on the tail wheel to holes "inboard" of the rudder cables at the servo control arms.

Good luck.
Carlos