Hi dvanden75,
Welcome to the Heartland Owners Forum and Family. We have a great bunch of people here with lots of information and all willing to share their knowledge if needed.
I can't help you with layout for the pin box area, but someone will jump in soon I'm sure that has run cables for the backup camera. And for those that are wondering,, the 3494QBS is a Big Country 5er.
Enjoy the forum and your new unit.
Jim M