ArchHoagland wrote:
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We will be coming into the state from the south from Oregon on I82.
I'm thinking of hitting Spokane then north on 395 to HWY 21 and follow it to Manilla Creek road and head west to The Grand Coulee Dam.
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That Spokane reference might throw people. That's the entry point if coming from the east on I90.
I82/US395/WA21/WA174 is a fine way of getting to Grand Coolee. This mostly crosses flat irrigated farm land (and non irrigated wheat fields in the north). US395 is divided hwy.
An alternative to 21 would be WA17. This has town traffic in the Moses Lake area. But further north it follows an ancient canyon with lakes and 'dry falls'. At US2 take WA155 along Banks Lake to the dam.
Banks Lake is a reservoir filling one of those glacial age canyons. It's water is pumped up from the dam, and then distributed to the irrigation canals. Beware that all Columbia River crossings involve a drop and then a climb (including I90).
Options for crossing the Cascades include:
US2 to Wenatchee on the Columbia. Leavenworth is a Bavarian themed tourist town. US2 puts you into the north suburbs of Seattle, with good access to the Everett Boeing plant.
Or you could take WA20 over the Cascades (through North Cascades NP). WA155 takes you to Omak, then WA20 crosses a pass to Twisp, then through Winthrop (western themed town), and on over Washington Pass.
Another sequence to Twisp is 174/15/97/153. This stays closer to rivers.
WA530 is a good way from US20 to Arlington and I5 south. Parts pass through a tunnel of big leaf maples. While Darington is a logging town with good access to mountain hiking, there are no passes to cross (just a low river divide).
While the bridge collapse on I5 complicates travel around the WA20/I5 junction, it does not make it impossible. Locals would like your business. But you could continue on WA20 to Whidbey Island (lots of great state parks). The ferry at the south end puts you into Boeing's back yard.
Camping close to Seattle is limited. Lake Pleasant in Bothel is most frequently recommended as full service RV park. Snohomish County has camping in several parks north of Seattle (Kayak Pt, Wenberg, Flowing Lake).
As for your exit -
take the ferry (or WA16) to Kitsap Peninsula, and then Hood Canal bridge to the Olympic Peninsula. Or catch US101 north from Olympia. Then loop around Olympic NP. Port Townsend is a nice Victorian era town, with good state parks. Or skip the Olympics and take 8/12 to Aberdeen. Some don't like US101 along the coast since in passes through a lot of clear cuts. But there are side roads like WA105 that stay closer to the coast. Most of the southern Washington coast is beaches and lagoons, not bluffs.
These routes skip the whole south Cascades (Rainier, St Helens). WA410 and US12 are the main highways across this part. NS routes through the Cascades are not as common as in Oregon.