We rode it last summer. We were staying in Friday Harbor, so we just hopped on the ferry. I have to say that the ferries were on time as promised and great. However, getting to the San Juans from the east coast, with 2 huge suitcases and 2 bikes in suitcases was more exhausting than traveling to Europe!
The island is flat and rural. The hill out of the ferry is well, a hill, but other than that, I don't remember anything. There was one area, not too far from the ferry where there were a few restaurants, and we ate there. Frankly, not that much to do there! It would be nice for renting a cottage and relaxing for a week, but after we rode the whole island, we had just missed the ferry and there wasn't another one for a *long* time. We got a snack at the restaurant by the ferry, (which then closed) and sat on a hard bench and waited. It was freezing and getting dark. Thankfuly, I had arm warmers and leg warmers to put on.
Maybe I am jaded. I am glad I went there, but I actually enjoyed the 2 days we spent in Seattle more.