I'm sure you will have a great time -- don't forget to plan around the
August 1 long weekend.  With the weak Canadian dollar, last year the
ferry's were booked solid, as were most accommodations and parks during the
weeks before and after.  (Multiple competing events: Ironman in Whistler,
music festivals, etc).

Also, in case you are not familiar, the HOH RIVER VALLEY access on the
Olympic peninsula has some of the most accessible, beautiful and diverse
hiking I have seen in this area (Van Isle, etc).

Cheers