Take Keller Peak road for 1/2 mile. Look for the big turn out on the right. Go around the closed gate. Follow that road until the first fork. Go left. Follow the road until you see a road go off on the right. Take that!

Look for the ribbons and follow those. At close to the top, you will see two ducks on the right and ribbons going up that way. That's the way you go. If you are like us, OTOH, you'll miss this and keep following the road :D If you go this way, once you get to the "front side", look for the trail heading up behind you. Follow that. On top of some boulders you will find a can to register your hike :) Mill Peak!

Round trip from Highway 18, Mill Peak and back is ~4 miles or so.