Lycan,
I have been riding different sections of the KVR since 1978 and have watched it gain popularity by all sorts of folks: walkers, bicyclists, horse folks, quadders, drunks in pick-ups ,and good folks like you and me. I rode the Myra Canyon trestles before AND after the fires (respectfully when encountering others) and have watched ranchers/farmers/ aboriginals lay claim to "right of way".
Each group has its own sense of entitlement to the railbed.....just have to say I will ride it when I want, and will find a way around the human obstacles best I can with a wave, a smile, and perhaps a polite conversation....
It sure opens up a lot of nice terrain...