Haha...
Well I can tell you that a lot of dust gets through the cabin filter. When offroading, you can see it collecting on the air vents and where the air vents blow. Maybe they make a hepa filter for the cabin?
Other than when I open the windows when offroading to make it more outdoorsy, I think that's where most of it comes from.
But yeah after a trip I vacuum with a big brush, then with detail brushes in the cracks and hard to get areas, then a complete damp microfiber wipe down and it's good as new!