I would suggest you just posting something here saying Im riding on this day leaving this place at this time, anyone interested. I feel that you might have better luck that way.
I tried to organize rides on the weekends with people from my church and I kept getting the scheduling nightmare, but when I started just posting times and places I was surprised at how many ofthe "busy" people found time to go.
dont expect to much at first but if you're going to be riding anyway it wont hurt to post the times and see who shows up.