Trek on 1/29/2014 4:40:08 PM:
David,
The water at the trailheads is normally turned on April 1 and off November 1. Our weather of course can vary greatly which makes for good riding well ahead of April 1 some years. And, later than Nov 1 too.
Some trail specific businesses may roughly follow April 1 to November 1, but to my knowledge most restaurants and B&B's are open year round. It's usually best to contact specific places for lodging, transportation, etc. to find their specific open/close dates and hours.