We are looking to rent a cabin, but are not sure which island would be the best to rent on. Privacy, but civilization when we need it. Thanks!!

I like Orcas best-it is still scenic and hilly but has great restaurants and hotels. Not quite as flat as Lopez-but Lopez is easier biking.

Lots of people like San Juan Island as well-it and Orcas are probably the most "well travelled"

I visited Lopez Island twice, the last time was at least 5 yrs ago, so I don't know how the island has changed. I stayed at a marvelous B&B called the Inn at Swift's Creek. It was very private and lovely. Fabulous breakfasts and a private hot tub in the woods that you could reserve for yourself to guaranty privacy. I had no car and so rented a bike and got around the island by bike. The Inn had an old beat up car that you could use to go to town in the evening if you didn't want to bike. You could bike anywhere on the island because it was so small. I adored Lopez - at the time it was quite rural with a wonderful tiny little downtown. The downtown had a bookstore, a crafts shop and two or three wonderful restaraunts. There was Holly B's bakery which had fabulous breads and muffins and the locals gathered there for coffee and gossip. You can always take the ferry to the other islands for day trips.

The Inn at Swift's Bay sold to new owners over a year ago. Lopez is flatter and quieter. It doesn't even have a town really..just a few shops in one place. San Juan has the biggest town.
Orcas has more hippy types (20 year old ones) and is hilly. Town of Eastsound is far removed from ferry landing so a car is most helpful there.

All are wonderful but you can't really top San Juan Island for the criteria you established. Lonesome Cove Resort with only six cabins is a sleepy hideaway on the north end of the Island. Much larger Roche Harbor is four miles away (restuarant, store, boat rentals). Fine small island town of Friday Harbor is about twenty minutes. Rates are reasonable, cabins are rustic but comfortable. Whales went right through the channel out front. Alas, reservations are tough to come by. Good luck.