Solar panel wire routing

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I am about to install an AM Solar system on our 2008 23' CCD Aristream. I don't want to make any holes in the roof & there is no fridge roof vent on this model. Has anyone ever used the vent pipe from the black water tank that exits through the roof to route your wires? If so any tips?

My plan is to drill a hole in the pipe just below the cap. The vent pipe runs in a wall between a closet & the bathroom. I need to drill an exit hole in this pipe, then route the wires through the closet, under the sofa to the controller which will be mounted close to the buss under the dinette.

I believe the hard part will be finding the vent in the wall between bathroom sink & closet. I don't know how much of the closet I will have to unassailable to locate/expose the vent pipe in order to drill exit hole for #8 wires. Again....any tips?

Thanks in advance for any help