I'd be very surprised if your digital signals suffered from resistive drop. Also, FIRST uses some very slow signals, so I again wouldn't panic.
For more information on the GPIO signal pins, you should look up the
NI 9403's
Operating Instructions and Specifications.
For information on the power supply capabilities of the DSC, look in
section 3 (page 27) of the control system manual.
I'd be much more concerned with the amount of noise coupled in over those 14 foot runs.