Tears in the rubber sealing strips get replaced or repaired. Windows, doors, wherever dust comes in has to have attention or you will end up eating dust the whole trip. I carry 35mm film in the factory cannisters. It seals well. You would be surprised how much dust gathers on them, dust that would be filtering down to your gear without the protection.
Cameras are precision machinery.
If you have digital gear or tend to carry a lot of nylon in the vehicle-carry a can of some kind of static neutralizing spray with you. Static attracts dust. As I said, it is a mental crutch more than anything here as I can almost read with the static light show when getting in and out of sleeping bags in the dark. I don't know anything that really helps here. When it is too cold to use a damp cloth for wiping you can guarantee static.