Dust proofing Campervan

Yep - hate dust I do - dunno about the Transit types but all cars have this problem - the more 'shed-like' the rear profile, the worse probably. Air flowing over the shell creates a slight vacuum within. My habit is to check the door seals - clean them even with a damp cloth if required - then run your dash fan flat out (or as loud as you can stand) whenever you are on dirt - positive air pressure in the cab is the biggest tactic you can employ in my view. Leave the fan off, or worst still, leave a window down and it's curtains (of dust :-o).

Hi Ianwa ,We have a Ford Transit Bus it travels 36 km's a day on gravel road and is full of dust, every 4 weeks we vacuum 1.2 kg's of dust up. I suggest you sell it.Ours has done 90000 km's and has five major breakdown's after all it's a FORD , FIX OR REPAIR DAILY. We are negotiating local council to buy back their dirt back.

Dust is probably coming in through the water drain holes in the bottom of the doors.
I tape all but 1 up and stops most of the dust.
You might want to have made a rooftop dust deflector or they might even have that accessory.
Also look for missing rubber grommets at the bottom of the side panels behind the mudguards.
You'll have to get down underneath to look.
Ask your missus she might go down for you. :>))