We rode Olallie for the first time today and agree with KentKangley, great bottom, more work on top.  We did not get to the end but made it to the only question mark on the route, which is the y where the uphill trail goes to Mt. Washington.  You will pass several other Mt. Washington trails but this is the only place there is a y that makes you question which way to go.  Olallie trail goes left and down the hill for what should be about 1 or so more miles.  We also question the rated vertical as two diffferent Strava readings were over 4100 vertical and 19 miles from the parking lot and back to where we stopped so be prepared for a big climb.

Great trail, great views and coming down was a blast.