Here's all of the bits...
The IMU should be stuck down with double sided tape as well as the GPS pod on the top of its mast, they provide a few bits of tape with the kit but I think those are intended for the GPS more than the IMU. I use servo tape on the IMU and that seems, to work fine. The control box and RX I just have velcro'd to the deck above the IMU which is stuck to the middle of the top centerplate.
There's two parts to the GPS cable, the one going from the pod to the control box and another that runs from a junction box in the cable down to the LED. The main GPS cable between pod and controller I'd guess to be about 7 or 8 inches long and the section for the LED probably about 16 to 18, hard to tell accurately without disconnecting all of it and actually putting a ruler to it.
Ken
P.S. that LED display is blindingly bright at close range, I have to put a piece of electrical tape over it when powered up in the house!