I could tell immediately that it was a female crab spider of the genus Philodromus, and one of the "Philodromus imbecillus" group (about 10 closely related species, of which only one, Philodromus insperatus, is known from Washington). To tell which species it was would require dissection, which I couldn't do on a fresh specimen not yet fully preserved. So I set it aside until I came to that collection in the course of curating and cataloguing last year's material in the order in which collected.
Having done so, I found that the internal female genitalia does not match insperatus (which occurs mainly in sagebrush country anyway), and is similar to Philodromus marxi, a species of the Atlantic states that has very different, metallic body coloration. So as far as I can tell from one specimen, it's a new species.
Several more steps must be taken before Crawford's new species will officially be recognized, one of which includes going back to Foster Island and looking for more of the little buggers.
But for now, if you see a tannish-yellow spider crawling around your house, be sure and compare its internal genitalia to that of the Philodromus insperatus before you smash it with a newspaper.