$7 Parking Fee or Sonoma County Regional Parks Pass displayed on vehicle dash.
If you start out going to the right, you'll get the tougher portion of uphill out of the way. There's a bench near the top of the first hill (just a few hundred feet in) that's great for taking in views of the east and catching your breath from the small hill.
The hill then moves down and the trees and brush open up to views of the southwest. There's another bench there as well where you can watch the cattle graze on the grassy knolls below, or catch vultures or hawks gliding in the air up above.
Immediately after that second bench, you'll turn down into the well-shaded portion of the loop on the way back to where you started. Keep in mind, this is all backwards if you choose to take the left path first!