can't be much help in the what to do area, as we only had a couple days, so basically did a driving tour....but accomodation wise, we stayed in the park lodges and were quite happy with them. Our fav was a lakefront cottage at Lake Crescent, followed by Lake Quinalt. And, altho reviews in other places have been mixed, we had good meals in both places, too. The best rooms sell out really quickly, so make your res ASAP. Here is info:

Olympic National Park Lodging Call 1-866-875-8456 or Book Online!
www.nationalparkreservations.com

We took fold up chairs and food (cheese, crackers, fruit,etc) in the car with us so we could stop whenever....there is not a restaurant on every corner, but there are lots of beautiful places for an impromptu picnic!