If I recall correctly I ordered 30 ft of cable and that covered the length.  There are 3 conduits running aft and there will be room for the cable.  You should plan on removing the hanging locker in the aft stateroom to get better access to the conduits and the opening into the hell hole under the electrical panel.
 
Bob
 

That is the length that I ordered.  I know that I didn’t use all of it, but what you are going to dine is it’s not a straight run back.  If I recall there was 5 90 deg turns in the hanging locker section alone.
 

Greg - I can't give you a length estimate, but will give you the heads up that depending on how much electronic stuff you are planning to have in the pedestal-mounted pods -- and the size of the connectors -- you may also have to consider swapping the 1" pedestal guard for a 1-1/4".   We had to do this on our boat the last time we did an electronics upgrade, because the connectors simply wouldn't have fit along with all the other wiring (particularly with a bend in the tubing to negotiate).
We're currently doing another upgrade of electronics, and happily the newer stuff -- such as the 3G radar -- seems to have significantly smaller connectors and cables.