Dirt ingress into cab

[alia176]

I just finished upgrading all suspension parts and had to take apart the interior pieces in the rear for rear strut bolt access. I live on a dirt road and noticed dust under the seat, rear deck and side interior pieces. Question is, how is the dust getting into the cab? The trunk is also full of dirt/dust as well once you lift up the trim pieces. Perhaps this is how the damn mouse is getting into my car as well?

I expect dust on the dash board just from driving on the 1/2 mile of dirt road with open windows. But I shouldn't be seeing dirt under the trim pieces or under the rear seat.

Ideas?