Disclaimer: I'm an old guy (57) and I haven't been on my MTB for a year and half, so what was tough for me may  not be for young folk.  ALSO- I have Verizon wireless service and I get bubkus when I enter Moran State Park.  Apparently TMOBILE is the provider to use on island.  The only reason  I mention this is I couldn't use Trail Forks, or RidewithGPS my entire ride,  Fortunately, I know locals and got great directions. There are FREE maps at the bike store in Eastsound.  Just Beware.

Mount Constitutin RC to Cascade Falls Parking Lot - We started at the parking lot for horse trailers down near the old education center.  My buddy had never done the section of trail from there to the Cascade Falls Parking Lot.  Nor had I.  It was a suck fest.  It's mosty up hilll, lots of hike a bike in the first section. Then the trail levels out for a bit, but there was still a bit of hike a bike.

From Cascade Falls Parking Lot, I rode ( buddy got a flat) the access road which continues to climb, but was much more manageable.  Still had  to stop and catch my breath a couple times but I made it.  Seemed the higher I went, the wetter it got.  My advice is to pick a puddle, and keep that line until you come out the other side.  Only time I slipped was trying to switch lanes in the mud.  Not that bad.

I heard a local refer to this as the Dam Ride.  If you go up the road and only take the 2nd left, you end up at the Mountain Lake Landing, where the group campsite is etc.  This is not technical at all, very nice double track, and considering the rain they got in January, in pretty good shape.  Would defintely do this ride again.  Not the longest- there is more to ride, but I was done, and just bombed down the mailn road to Cascade Lake again. Didn't see another person the entire ride. Great ride and great workout!