Great idea Steve, I was thinking on the same lines as that's how my dad's 22 ft fishing boat was controlled using cables in tubes with pulleys in the corner and a forward steering wheel / helm in cuddy / cabin.
Where is the rudder hinged? in some pictures I've looked at it appears to come up through a narrow section of rear deck. if so then hide a drum on the rudder post below that deck and wind control strings around it and routed to another drum on the servo.
HI Rick, long time since i have seen an Africa Queen, seem to remember that i used an aircraft flexi lead, this went round the stern and along to the servo. They come in 3ft lengths and replace the pushrod.