A lot of hops are grown in western WA, even more in eastern WA. Ditto Oregon's Willamette Valley. In fact the PNW is the largest commercial hop growing area in the country. Pretty much any kind will grow well here and there are numerous varieties that have been developed in this area - Willamette, Glacier, Mt. Hood, Cascade, etc.

Hop vines get big and grow fast (upto a foot a day in season), so you need a lot of room and a sturdy, tall trellising system in full sun. Generally the flowers are harvested in late summer or early fall. The vine is herbaceous - that is, it dies back to the ground each winter - so clean up is easy. Just wait until after frost kills back the topgrowth and whack it off at ground level.

I grew the ornamental golden hops (flowers can be used for brewing but not considered as flavorful as other types) for years and finally removed it as the roots migrated extensively to areas where it was not wanted and its long, vining and prickly tendrils kept grabbing at my dogs as they wandered by and tangling in their fur. Had to effect rescues several times :-)

Thank you, gardengal,
I did not think about migrated roots. Don't think that i want hop anymore in my garden.

What vine can be considered for covering gazebo? I am looking for something that will cover it fast in spring, will not be difficult to clean in fall, useful in some way (flowers or fruits), will not require a lot of pruning.
I was growing achocha for several year around this gazebo. Great looking leaves, edible fruits, but ... it's annual and grows very slow in spring and beginning of summer and does not cover roof by the time when we need to have shade.

A good annual vine is Phaseolus coccineus.

Yes, scarlet runner bean would be good, altho won't grow much until warmer weather comes...forget getting much coverage in Spring. The beans are edible, but not "choice". You could also consider edible pole beans, altho the flowers may not be quite as ornamental. Morning glory offers good color.

I'm not sure any of the above are going to give you the extensive covering you're looking for. I can't think of any annual vine that will grow as fast or tall as hops (which of course, isn't an annual).

Is the site sunny enough to consider a more permanent vine? Kiwi? Grapes? Honeysuckle? Climbing rose? Evergreen clematis?

I have several 1-gal. pots of golden hops that I'm going to plant against my large back porch. There are no flower beds nearby that it can invade...pretty sure I can control it there. The porch is ugly & could use some covering up. Besides, I have childhood memories of my grandmother growing hops along her tall porch.