Well I originally posted this is illumination but haven't received any responses....

I've decided to build a roof rack. I just don't know where I can drill into the roof for the base... I'm going to do something similar to the link below and I've added a picture for reference of my roof... where can I drill into? Is there a roof frame I can screw into? The parts labeled 'cross bars...' is how I'd like to do the base.

https://www.f150online.com/forums/ot...roof-rack.html