About the ferries...

The ferry is the lifeblood for those in the tourism industry here... the ferry we were on today holds 2,500 passengers and 144 vehicles.  Unless you feel the need to drive around San Juan Island (most people come here as a day trip), there is no need to bring a vehicle - you can easily walk all around Friday Harbor.  Need to get to the other side of the island?  You can rent a car, mopeds, take a cab, or there is a shuttle bus for $15 per person (all day).

The cost for putting our truck on the ferry is around $70, plus $12.45 for each additional passenger. 

The ferry workers do an admirable job of getting all those vehicles on and arranged, all in a relatively short period of time.  Multiply that by six times daily from Anacortes, other inter-island ferries, and one that comes from Sidney (Vancouver Island, Canada)... and you can see that they bring a LOT of people to San Juan Island each day.  Or, you can get here by private boat, private airplane, or Kenmore Air (a sea plane company that flies out of Seattle to many different places in the area).

Just giving you some options... if you decide to come this way.