Doing my setup was rather easy, as I ran conduit all the way from the generator to the transfer switch - a 75-foot run. Running three additional #12 wires for the 20-amp receptacle that I put in my generator's cabinet was a simple proposition.
First, let me say thanks to everyone for your thoughts. Now if I need to run some wires around 30+ feet.... and never ever want to do it again ... and be able to switch 5 years from now to another generator or even another brand of generator; how many should I run. One did I hear 18 guage for the T1, how about the 0 wire, a separate AC line for a battery heater....?
For your setup, my choice would running a separate 1/2" conduit between the generator and the ATS. Then, running additional wires for whatever reason would be really simple to do.