Bought my first canopy a few months ago. Have noticed when driving on dusty roads that a fair bit of dust gets into the canopy, and all over my stuff! I took the canopy off and redid all the weather stripping. Didn't make a noticeable difference. Pretty sure it is entering around the rear window, and/or around the tailgate.
I don't expect to 100% stop dust from getting in. Obviously there is no way to completely seal up the gaps/cracks around the rear window and tailgate, but hopefully there is some way to minimise it from getting in?
If not perhaps I'll just throw a big blanket over everything and shake it out when I get to my destination.