The Blue Butterfly Inn isn't readily spotted from the road; look instead for the Yosemite View Lodge, which you can't miss. It's the last building (actually, a whole series of buildings) along Highway 140 before you cross the boundary into Yosemite. The Blue Butterfly is located a little west of center on the grounds of the Yosemite View Lodge; a minute or two wandering through the parking lot should suffice to find it. It looks like this.