Are you building it as a trike or a taildragger? My first thought was just to flip the servo tray over, and mount the throttle servo on the opposite side of the fuse, but that does conflict with the nose-wheel pushrod if you set it up as a trike.

I just looked at the manual, and it has plenty of pictures of the setup with either a four stroke or a two stroke engine.

The thinnest sullivan wire is flexible and lightweight, gives you lot of freedom to route it anyway you like. I have even used it for ailerons and it can take a 90° bent with a radius of about 1-2", without any problems. If you use it for the throttle don't use metal all the way as you might get radio interference on 35/40 MHz.

[link=http://www.sullivanproducts.com/GoldnRodMainFrame.htm]scroll down here[/link]

OK, I just got back from the local hobby store. They had the Sullivan S507 in stock and it fits the bill for the throttle, is very flexible and has a bend radius of 2" or less.
It should work just fine for this application.
Thanks for all the replies!

It is a tail dragger the way I put it together which I prefer from years ago. The servo tray was already glued in place in this ARF so reversing it might have been a problem.
But the Sullivan cable I bought (see above) should work just great.