Lopez Island is one of the San Juan Islands in Washington State. To get there you need to drive to Anacortes, Washington which is about a 2 hour drive from Vancouver. If you have a Nexus card that helps with the border crossing.
Once at the Anacortes Ferry Terminal you can park the car and take your bicycles and camping gear across to make things easier. Then you don't need ferry reservations or to worry about the costs for a car. It is cheaper to take the ferry as a cyclist. It's quite common so you can just follow the other cyclists and do what they do. Remember that cyclists offload first so be ready when the ferry arrives at Lopez.
Lopez Island is perfect for cycle touring because after the ferry traffic passes, it is pretty quiet. They have a main road for cars, and cyclists can take the side country road to the Spencer Spit Campground. The scenery is beautiful and the beauty is the serenity of the road with the wind in your hair. As a beginner cyclists it was a perfect bike ride to the campground with country roads all to yourself. I wish I spent more time there and will put it on my bucket list to return. It's worth a weekend trip to San Juan Island to spend time on Lopez Island and I only had a small taste of it. I'd love to return to truly explore.
Washington State Ferry Schedule
Anacortes, Washington Google Map