Installing a Rooftop Fan for micro camper conversion

[Jai Bunney]

Hey guys, I'm converting my 2005 TW VR Magna Wagon into a micro camper and am wanting to cut a hole either directly above where the passenger seat is or centre front in the middle of where the passenger and drivers seat is.
I'm mainly concerned with ruining the structural integrity of the vehicle as I have a roof rack with battery, gas bottle and roof top bag on the top and don't want to risk cutting into the frame if it'll mean it could sag etc. (I'm still within the weight limit too)
I was also wondering if there are any links to any diagrams out there showing where there are specific beams and such that I either need to avoid cutting into or near etc.
I am also wanting to add maybe one or two Louvre vents on the bottom of the front side passenger door and right side back passenger doors for air intake, as the roof fan will be the exhaust fan. The door vents I feel should be easy enough, I just worry with the roof..
Please any advice would be amazing!!

[GRH]

tap or knock from above the car you should be able to find where the support beams are.

[GRH]

on the other hand i'd personally avoid cutting a hole in there.. especially where a passenger might be sitting.. any weird thing happens say something drops on the car or it rolls, whatever on there will shoot into the cabin.