Did this route on Saturday July 23rd 2022, wasn't sure which side to start from so biked first to the Whickersham Truck Trail by Lake Whatcom Park, steep uphill on a very rocky gravel road until you get around Stewart Mtn which is the most difficult portion of the route, I hiked a lot of that portion. After Stewart, it begins to level out and becomes more rolling hills, great views of Lake Whatcom, Skagit Valley, Mt Baker, Twin Sisters, then goes through a logging area so might be better to go on a weekend when nobody is working there. After the logging area, it starts to become mostly downhill from there. Route is overall beautiful, recommend checking it out, bring plenty of food, water, sunscreen etc