I live in Yakima...our phonebook has a great map from this website showing about 25 wineries south of town.
www.yakimavalleywine.com There are also a few tasting rooms in downtown. Plan on about a 2 hour drive from Mt. Rainier to Yakima if you are coming from the lodge at Paradise. In the summer the parking lot at Paradise fills up by about 10:30 or 11 on a nice day. The lodge is very nice there, although we never have stayed the night...