Parking is often easier to find at the Beverly Canyon Trailhead, and you get to ride some very fun singletrack instead of the normal fire road on your way to Mormon, National, and all the other goodness of SoMo. Tacking this onto the beginning and end of a East National Loop
ride is highly recommended!
From the Beverly Canyon Parking Lot, go west and a little south. You'll cross a few washes and eventually face a pretty significant climb to the top of a ridge. From there, it's a short and steep, but very doable, descent into Pima Wash, where you'll meet up with Mormon Loop Trail