+1 for the TowPro, you can also mount the 'box' in any direction; so long as it is firmly mounted.
The P3 on the other hand, HAS to be mounted longitudinally, AND you should be able to see it AND be able to operate the lever on its underside.
+1 for figure 8 cable and connecting into the lights; much better then mucking about with the pedal.
While you've got the interior out of it you can run the 6B&S to an Anderson connector at the rear.