Glacier point is the de facto iconic view of the Yosemite Valley proper. While nothing can be taken away from Glacier point, Washburn Point is also not to be missed on the way. The drive to these two vistas is about an hour from the Yosemite Valley floor, and passes by the renowned Tunnel View vista. If you only had one time to view it then the Golden Hour at the end of the day would be the best time, or sometime during the midday.
The parking lot at Glacier Point is the first clue to the magnificent scope of this observation area, and can easily hold several hundred cars. The observation area is wheelchair accessible with bathrooms, and a gift shop/snack bar.
We came right after a large fire that had Yosemite closed for several weeks; we almost cancelled the trip because of the smoke. Even though there was a lot of smoke the beauty of this Granite Shrine still shines through.