One thing about Seattle is that there are a lot of neighborhoods--each having its own character. Some of the main ones are: Fremont, Ballard*, Capitol Hill and (closer in) Belltown. Researching these names may give you some idea of which you'd like to visit (in addition to downtown, of course). The first few times I came to Seattle as a tourist, I just kept getting stuck in the downtown, unsure of what else there was to find. (With the exception of Belltown, these are not reachable on foot.)
*Ballard has one of the best farmers markets around--it happens on Sunday and all the little shops and restaurants that line the street are open. Also, I really (really, really, really) like Asadero Mesquite restaurant in Ballard. It serves all variations on carne asada and I think it's the rib eye steak that I like the best.
I live near an outdoor, strolling mall called University Village. The shops are typical yuppie stuff (BR, J Crew, Madewell, GAP, Aritzia, Joie, Eileen Fisher etc.) but the setting is pretty, with engaging statuary and flower baskets. https://uvillage.com U Village is reachable by light rail with a walk of about half a mile(?) past Husky Stadium to the mall. Yummy restaurants, there, too--I like BaBar (Vietnamese), Din Tai Fung (Noodles), and the BBQ Pulled Pork Pizza @ Elemental Pizza Pi
As far as food and nightlife goes, I recently discovered the Starbucks Roastery out on the Pike/Pine corridor--so pretty (especially at night with the light twinkling on all the warm copper fittings.) http://roastery.starbucks.com This area has recently undergone some gentrification and is home to quite a few yummy restaurants.
Re: outfits--we do not get a lot of sideways rain, but I think shorter skirts will be too cold and bare for outdoors wear at this time of year. And you may want to pack a puffy to layer under your trench.
