Ernie,
My dealer installed my Trav'ler on the Bighorn. I have had this same Trav'ler on three rigs now. The first two times I installed myself. I have a location sheet describing the location of roof cable that was in the bag of stuff that came with the rig. I really don't know how accurate the information is and where it would be for your model.
Regarding the support. For all three installs I used the Winegard Sk-008 base plate for additional support. Link:
SK-008 It adds a lot of rigidity to the footprint of the Trav'ler. The screws that came with the Trav'ler work just fine.
The plate looks something like this mounted on the roof. Yikes, forget looking at the cardboard on the roof.
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