I went to Yosemite National Park this weekend and the waterfalls are spectacular. The river and streams were cascading with water as well. The large amount of snow high in the Sierras has made this a great time to visit the park.
Highway 140 into Yosemite National Park (through Merced) is closed due to a rockslide. For up-to-date road conditions call (209) 372-0200. There are other routes to take.
There are 3 wineries in Mariposa, which is on the way through the 140 if you want to enjoy some wine tasting on your way to the park.