Great views of Alcatraz and the bay. 2 decent climbs to get the legs burning.
This route starts and ends on Jackson street in the Presidio Terrace neighborhood of San Francisco. This loop can be started in several areas of the Presidio including off of the Lyon street steps, but this starting point creates a good midpoint of the loop.
Along the route, be sure to keep an eye out for runners and vehicles when crossing over the main thoroughfares to reconnect on the trail. Not only will you see great views of Alcatraz, Angel Island, and the Golden Gate Bridge, but you'll be immersed in a forest environment for parts of the loop, making you forget that you're in a city at all.