or you can skip drilling any holes in the roof, and just run your two solar cables down the rear roof ladder, thru the radiator cover, under the chassis, and into the Inverter bay and Battery bay to the Charge controller - like I did. I mounted the charge controller onto the side of my Chassis batteries, since they are above the House batteries, where I can see the controller anytime I open the bay door.
I have two 100w HQST panels, a 20amp PWM charge controller, as a package from amz, and the units came with mounting brackets and parallel connectors.... you'd only need several of your own wires to run from your charge controller to your Positive and Negative battery leads.
'14 Thor Palazzo 33.3 compact diesel 100k+miles since '14... US, Alaska, Canada...
AND a '14 Gulfstream Amerlite
AND a '07 ForestRIver Rockwood