You'll love the views you'll have of the EBMUD Watershed while you're hiking or mountain biking along Nimitz Way in both Wildcat Canyon Regional Park and Tilden Regional Park. The views really open up once you're in the area considered the Bay Area Ridge Trail and the East Bay Skyline National Trail. I'd encourage you to grab one of the printed maps you'll find at every trailhead in the park that is next to a parking lot.
If you park in the Inspiration Point parking lot, you'll end up exiting the lot and turning right on the Nimitz Trail. It's a lovely, rolling, paved path that turns into the East Bay Skyline Trail. It's up to you how far you'd like to go and whether you'd like to create a loop or do an out-and-back hike. With map in hand you can easily descend by taking a left off the Nimitz Way at several different points, such as Laurel Canyon, Wildcat Peak Trail, or Conlon Trail. Just know that your return back up to Inspiration Point via the Meadows Canyon Trail or the Curran Trail means you have some beautiful uphill terrain.
If you're a trail runner, a dog walker, or just someone that values a long walk in a beautiful spot to clear the cobwebs, Tilden Regional Park should be your go-to place in the East Bay.