Excellent idea. Other than street bikes I haven't gone on any cross country rides so air filters haven't been a problem. Back when we went to the dunes all the time I used this setup for my quad. I always had the convenience of a enclosed trailer to work on the bikes/quads.
When washing this keeps the crud from getting inside.
Most of the DualSport crowd I ride with are good about keeping air filters cleaned.
But NONE of them think about filtering the air THEY breathe. I can get a new bike if I don't keep the air filter clean, lungs are a bit harder to acquire. I always carry with me, 3M N95 Particulate Respirators part # 8511 , even on my street bike. Most times I'm ride leader with my group. Not that I'm the best at leading, I run dual GPS units. Zumo550 and 76CSx both Garmin products. Like NASCAR if your rider leader you breath clean air. I'm not the fastest rider and no one wants to be in the back all the time, so we swap positions. I just tell the new guy to just stop at the next intersection.