Sentinel Dome is a short 2.2 mile round trip hike from the trail head up off of Glacier Point road.  I recall having to park our little rental SUV at a fairly steep angle off the side of the road as all of the trailhead parking was full. 

But strangely there did not seem to be that many people on the trail.  Your reward for making the hike is an amazing view in all directions. It really is enjoyable to stare down into Yosemite valley and see all three vertical drop sections of  massive Yosemite falls across the valley.  Look at the picture at the top of the page and you can see how relatively small the falls appear.