From January to April, the crushed-limestone section of the PV from SR 4 to CR 28 is soft and as a result, becomes quite rutted from the bikes that ride the trail. Riding on it when it is this moist put a coat of dust on your bike frame, chain, derailleur, wheels, and usually your legs as well. And the ruts you create make it more difficult for subsequent riders to ride.
As as result, many of us avoid that section of the trail, and for those of us in Goshen, it means we just avoid riding on the PNT altogether because the cleanup involved is a hassle.
I suspect that walkers and runners also experience some of the same frustrations as the biker. Their shoes would become caked with dirt.