Griffith Observatory's West Trail is a short loop trail for a great workout or run with amazing views over Los Angeles.
The trail starts near Dell Picnic area, near the Trails Cafe. On this wide fire road, you can choose to run or hike, but don't expect to have the trail to yourself, especially if you're heading out on the weekend. With that said, you can time your run or hike around sunset and get amazing views before you head back down to the car.
On the trail up, you'll be able to enjoy views of both the observatory and Los Angeles. While you're heading uphill, keep an eye out for a path leading up to the observatory. The trail isn't really well-marked, but you should be able to sort the trail out pretty easily given how visible the observatory is. To finish the trail, continue downhill on the loop back to the picnic area. If you're just getting warmed up, head out for one more lap.
Once you're all set, head to Cafe Los Feliz for a quick bite and your next cup of coffee.