I will have 1 free day in S.M. in mid October and my hotel is right at the pier. It looks like there is lots to do right at the beach, but I would love to rent a car and go hike in the mountains, for the nature and the views. Would this be safe, as I would be alone, or would it be unwise? Where would you recommend as a good 4 or 5 mile trail or loop where it would be hard to get lost - and safe if alone? I am in early 60's and quite fit. I would be in my runners - not hiking boots. Thanks!