I live north of Olympia and September is usually nice weather (Indian Summer). Most of us Western WA residents live by the rule "if you don't like the weather just wait 10 minutes, it'll change". Tennis shoes are always good but you will probably want sandles too, best advice is be prepared - it can get in 70s during the day but temps will drop in evening. Right now we are having temps in upper 80s but only high 60s in evening so be prepared. Can't give you advice about quilt shops in the area as I haven't visited any down in that area, I have had people tell me that Bayside Quilting, which is in Olympia, is excellent.