345 -347 loop is a very fun trail. It starts up hill but on the way back its a very fast downhill and narrow single track with huge granite boulders in the trail you have to ride over it can get quit tricky at time thou but very fun for every level of riding.
How to get there:
From downtown Prescott take Montizuma north until it turns into Ironsprings Rd the you will see a sign that says to Granitt Basin turn right. Follow the road until the end and you will see the trail head.