Please review our itinerary:

Day 1 Arrive Seattle 2 pm get car, hotel, check in, dinner
Day 2 Explore Seattle
Day 3 Drive to Olympic - stay in Port Angeles, explore Port Angeles - sites along the drive?
Day 4 Explore Olympic National Park - stay in Port Angeles
Day 5 Ferry to Victoria w/ car, explore Victoria, stay in Victoria
Day 6 Explore Victoria, ferry to Seattle, stay in Seattle
Day 7 Open
Day 8 Fly Home

What do all think?????
Can you make reservations on the ferries?

There's no car ferry between Victoria and Seattle.

You can reduce costs by leaving the car in Port Angeles and taking the passenger ferry (summers) or just ride as foot pax on the Coho, then return to PA and drive back to Seattle. Otherwise you'd have to take the WA ferry from Sidney through the San Juan islands to Anacortes, then drive back, or cross over to the BC mainland from Swartz Bay to Tsawwassen and then join the potentially huge queues at the border, a long day.

You can reserve the ferry from PA to Victoria, the San Juan ferry, and the BC ferries from Vancouver Island to the mainland. You can't reserve the boat between Seattle and Bainbridge Island (where you go to get to PA and the peninsula.)

Exploring Port Angeles is quickly accomplished . Consider staying at Lake Crescent, Port Townsend, or some B & B in the Sequim/Dungeness area.

Is one day enough for ONP? Do you know if it is similar to Acadia?
Is there enough to do in Victoria for 2 days? Do you need a car in Victoria?
What type of drive is it from Seattle to ONP? Is it scenic, are there places of interest along the way? Is it advisable to take the ferry from Seattle to Bainbridge and then drive to ONP as a shortcut instead driving all around the water?

We are a 50 year old couple who enjoy the cities (we're originally from NYC) but we don't enjoy spending the majority of a vacation in the city.

What time of year?

Seattle to the Olympic Peninsula involves a (scenic) ferry from downtown Seattle to Bainbridge Island (a pretty but suburban island in Puget Sound) from which a bridge connects the road to the Kitsap Peninsula. You cross the Kitsap Peninsula (around 20 min.) and arrive at the Hood Canal floating bridge, which crosses Hood Canal, a very long inlet separating the Kitsap and Olympic Peninsulas. From there the drive (some bits scenic, some not) takes around an hour to get to Port Angeles. This compares to (IMO) a much less enjoyable (and longer) drive down around the bottom of Puget Sound - not worth it given your time frame.

Along the way you can stop in Port Townsend, an historic town with a wealth of very fine Victorian buildings; or (at the moment) great swaths of lavender fields around Sequim and Dungeness... plenty of diversions.

From PA it's a short drive up to Hurricane Ridge in Olympic NP - http://www.nps.gov/olym/photosmultim...dge-webcam.htm. As you can see, it's nothing at all like Acadia. Just to the west of PA is Lake Crescent, a very pretty lake with some decent lodging on both sides.

Or, around the west side of the peninsula (a couple of hours from PA) you get to the Olympic NP coastal area and the rain forests. http://www.nps.gov/olym/photosmultim...otogallery.htm Again, for the most part, not like Acadia.

Enough to do in Victoria? Sure - lots of cute downtown and around the Inner Harbour, great if expensive and touristy botanical gardens (Butchart Gardens) and some dandy coastal drives north of the city along the Pacific side.

Do you need a car? No, but it can help. If your time is limited, you can leave the car in PA, go over as foot pax, then take taxis/buses to the sights, and probably end up close to a wash on cost v. taking the car on the boat. We usually take a car because we like exploring the island away from the tourist zone in downtown Victoria.

Using our miles we will fly out of Newark to Seattle and keep to our original itinerary but eliminating day 7. Due to child care concerns coming home one day early works a little bit better for our once a year childless vacation. We can still get flights within the next 3 weeks so away we go.