Your map isn't even close... MUCH better map and directions on the Amir's Garden web site:
Best Picnic Oasis Inside Griffith Park Los Angeles 2011 - Amir's Garden
Ever want to get away from the city and enjoy a picnic without having to face crowds or a punishing hike? You can toss your picnic in a backpack and walk up the wide, easy fire road in no time to Amir's Garden in Griffith Park. Halfway up you'll pass Water Tank #73 — Amir's Garden is past the next curve. There are tables at the "entrance" to this oasis, where you can picnic while enjoying the quiet and beauty. Or you can explore one of the trails cut down the hillside, winding through greenery planted by the late Amir and more recent volunteers. Benches are spread throughout, so it's easy to find a quiet spot. If you bring some wine, make sure to raise your glass to the park-lover Amir Dialameh (park authorities prohibit alcohol on park grounds, so don't say we told you to do this) and thank him for this beautiful gift. Griffith Park Mineral Wells Picnic Center Fire Road, Griffith Park; amirsgarden.org.
—Reuben E. Reynoso