Scotttb has it pretty right on - I've stayed at/eaten/etc most of those places he cites and can second them. Apart from that a few things:
- All the National campgrounds are great and you can't go wrong with them.
- Allow yourself some time at the coast. 101 skirts the Quinault Indian Reservation so really isn't on the coast all that long. Stay at South Beach or Kalaloch and spend some time at the beach. Great lodge at Kalaloch and a little store so I've always stayed there. The coast is pretty wild this far up and while always windy and can be cold is fantastic.
- Plenty to do at Lake Quinault with a number of national parks there plus several commercial. Several lodges, restaurants, stores and so on.
- Take the side trip to the Hoh and spend at least one day there. Plenty of fantastic hikes, hot springs and rain forest info and such there.
- I took a side trip up to Neah Bay and hiked out to Cape Flattery (the most NW point in the state). This was well worth doing and the road - which is a there and back situation - is incredibly scenic. You can get to this by turning left (NW) onto 112 where the route splits off of 113 (heading east on 112) if going CW. Neah Bay and the Cape are on the Makah Indian Reservation
and there is apparently camping up there which I hadn't known so I camped just outside the Res at Snow Creek Fishing resort which is a fisherman's place but has a nice wooded camping area off from the main boat ramp. http://www.snowcreekwa.com
- Port Angeles has several brewpubs if that's your thing (it is mine!) Peaks
is great and there is another tiny one just a few blocks from there: Barhop
There is also a great Co-op where you can get bulk foods along with all the other amenities.
- Definitely stick with the Olympia Discovery Trail. From Port Angeles it heads right to Sequim Bay State Park which has h/b sites and is a cute little park on the bay.
-Port Townsend of course has the Port Townsend Brewery and the Pourhouse, both south of downtown by the marina for the beer drinking. In downtown proper among the bookstores and knicknack shops are several cycling shops if the need arises, Waterfront Pizza which has HUGE slices, Elevated Ice Cream which makes their own and Better Living Through Coffee - my favorite coffee shop on the peninsula.
There is of course tons more. If you are going to Anacortes and beyond I have a much better route than the Adventure Cycling Route plus plenty of info on Whidbey, Fidalgo, Anacortes, Skagit Valley and so on. Anyway this is a beautiful area that I really love so you'll have a great time. Enjoy the ride!