Tilden is a big regional park in the hills above Berkeley. Lots of recreation: an old carousel, model steam trains, lake swimming (which might be fun in summer, hmm), botanic gardens; but today, it's hiking.
We drove in by the scenic route, from highway 24 up Fish Ranch Road and Grizzly Peak Boulevard to enter the park on Shasta. A bit further than we needed to drive (the quicker way is to come up from Orinda on Wildcat Canyon Road) but worth it for some fun driving and spectacular "let's pull over and look" views over the Bay.
The easy walk is an out-and-back on Nimitz Way: park at Inspiration Point, and walk out along a (relatively flat) paved trail. Good views, but it's a little dull and its very busy: lots of strollers, cyclists, joggers, and rollerbladers.
We took bahiker's route, which is a good one: it starts at Inspiration Point, but drops down from Nimitz Way immediately, and you're very soon alone with nature. bahiker says "moderate side of easy"; Melinda disagrees. The "moderate side" part is a stiff pull up from the valley back up to the ridge to rejoin Nimitz Way near Wildcat Peak: this part's a bit of a slog, but it's worth it for panoramic views from the peak (right around to Martinez's oil plants to the North-West). Wind down with an easy paved 2 miles on Nimitz Way.
Almost lost the trail twice though. Once at the start: Curran Trail starts immediately inside the Nimitz Gate, before the toilets; if you go 100 feet you've gone too far. It's muddy and doesn't look like much, but it dries out and widens soon enough. And again down in the valley, turning off Wildcat Creek Trail: bahiker has you look for "Wildcat Peak Trail", whereas the park maps simply name it as "Peak Trail". And because it's in the Nature Study Area, it's labelled with a symbol rather than by name. Anyway, when you come to a wooden plank bridge over a small creek to the left, labelled with a hill symbol: that's the one, take it, and follow that symbol all the way up.
Most of the forest in Tilden is eucalyptus, and it feels like walking in a prehistoric forest: tall spindly trees thrusting up towards the light, strips of bark peeling off their trunks, and heaps of shed dead bark under each. And since seeing an Anna's hummingbird staking out his territory in Huckleberry, we now hear hummingbird song everywhere: they're common and very territorial. But nature spot of the day went to Melinda: a group of turtles hauled out onto a log and basking in the sun on Jewel Lake.