If you are in SF: some of the best running terrain in the west is just over the Golden Gate bridge. Hop on your bike, ride to the Marin headlands, and go for a walk. If you're already pretty fit, go for a run. The trail network is amazing and you can go as far as you want.
If you are on the Peninsula: you're next to some of the best road biking on the west coast. You can make tons of loops up to Skyline Rd and they are all awesome. For starters try starting down in Palo Alto and riding over Arastradero to Alpine Road, work up to climbing Old La Honda.
If you are in SF: some of the best running terrain in the west is just over the Golden Gate bridge. Hop on your bike, ride to the Marin headlands, and go for a walk. If you're already pretty fit, go for a run. The trail network is amazing and you can go as far as you want.
If you are on the Peninsula: you're next to some of the best road biking on the west coast. You can make tons of loops up to Skyline Rd and they are all awesome. For starters try starting down in Palo Alto and riding over Arastradero to Alpine Road, work up to climbing Old La Honda.
Why go to a gym?