I've wondered about doing this. Is it reasonably safe to be riding up Mushroom?
I thinks it's signed as multiuse,two way, its pretty wide, should be ok, people should know by now to expect other uses/climbers on the trail. Might be an issue on busy weekends when the Ned Heads are getting their strava on!
http://mtbtrails.ca/ Author of Locals' Guide to North Shore Rides and Locals' Guide to Fraser Valley Rides.