Toad's / Iron Tread loop clockwise, but I've seen others do it CCW. There's one easy switchback on 3B. When you get to the top you intersect a fire road that's steep to your right. Go up that to the junction with another fire road, go left, downhill, then up a little and look for the top of Mr. Toad's to the right. After a couple sketchy switchbacks it's flowy and fun all the way down to the Oak Canyon main trail (be mindful of some creek crossings -- you can easily pinch flat on impact). Head due North on Oak, cross 2 or 3 deep creek beds, then look for a relatively flat trail heading off to the Northeast up a wide canyon. That's Iron Tread (IT). Switchbacks near the top are tough but rideable (I've seen a couple guys clean them all, myself not being one of them). During the last hundred yards near the top of IT you'll probably see an abandoned bulldozer tread on your left which gives the trail its name. Very shortly you're at the fire road where you came up from 3B and back down you go.