Ok, on most coaches there is a PILLAR called the "A" pillar (They are lettered starting with the front of the coach) where the windshield meets the side windows. This is usually right beside the overhead compartment
If you pop the caps and remove the screws and "Open" the pillar you will see a whole bunch of cables already hiding there.. add one more, Close, replace the screws and caps and you will have a cable under the dash.
I then went through an existing hole to the engine side, and mounted the ground block on the Brake Bell Crank Barcket under the hood. But you can then run id down the rails (Frame rails) to any handy compartment re-enter and mount a block wherever you wish.
