Originally Posted by Gardyloo

The road to the Paradise visitor center in MRNP will be open; the one to the other main visitor center on the mountain at Sunrise, probably won't open until July. It's been a very snowy winter on Mount Rainier, so at Paradise I'd anticipate there will still be 6-10 feet of snow on the ground (currently around 15 feet.) The parking area will be plowed and probably clear. It's worth noting that more often than not in May and June the mountain can be socked in, making the 2 1/2 hour drive from Seattle a little pointless. The NPS webcams on Mount Rainier are useful - Webcams - Mount Rainier National Park (U.S. National Park Service) (nps.gov)

On the Snoqualmie Valley route, there are lots of farms, and probably some wildflowers here and there, but it's mainly a dairying area (also some vine fruit like raspberries.) Remlinger Farms, just south of Carnation, grows a lot of flowers and might be enjoyable. Note the Memorial Day weekend can be crowded throughout the "Twin Peaks" zone around Snoqualmie and North Bend. Remlinger Farms | "ENTERTAINING KIDS OF ALL AGES…."