Dust Issue

My wife and I camp regularly in the state parks.  Many of them have gravel entry roads rather than paved surfaces.  While the roads are generally in good shape and easy to maneavor, a great deal of sand and dust is lifted from the roads by our tow vehicle.  The result, is always a lot of cleaning required inside the TM after we setup camp.  Has anyone else dealt with this issue and have you found a solution?  I have inspected the seals and find nothing that looks out of the ordinary.  Perhaps this is a problem we just have to live with.