This hike is on a very nice portion of the Skyline National Trail which starts at the Tilden Park Steam Trains parking lot, going to Redwood regional park, and returning. The hike covers EBMUD lands, and goes through several East Bay regional parks, including Tilden, Sibley, Huckleberry, and Redwood Regional Parks. The terrain and scenery actually varies quite a bit, from open, dry hillsides, to fern and moss covered grottos. Some portions are completely in the open, offering great views, while others are under extremely dense tree cover. You actually walk over the Caldecott tunnel on this hike, but I could never see the road or any cars, only hear them. Portions of the trail are in such dense greenery, you literally walk in tunnels through the brush. It's like being in a East Bay jungle!
The hike undulates a lot, so it can be hard to get into hiking rhythm. If you park at the steam trains, you will have a lot of elevation to gain at the end of the hike...something to save energy for. In the end, it's a nice hike with a lot of varying scenery. It would also be a good hike for hot days, as a lot of this hike is under dense tree cover. Many east bay hikes are on barren, hot hillsides, not good for summer, but this one has many areas which would be considerably cooler.
This hike is great for refueling...at least for water. Due to the many EBRPD parks in this area, there are plenty of drinking fountains along this route. The spur trail out to Round Top can be skipped, as there aren't many great views, and there are a bunch of radio antennas up there to ruin the scenery.