Máj lookout is definitely (one of) the most popular spot over the Vltava river. And there are various reasons for it. The area is rather spatious, it offers stunning views over one of the Vltava river horse shoe bend, and its stony surface and dwarf pine trees gives you almost a Mediterranean feel.
And yes, it can be really crowdy here, so if you like your privacy, there is an another bit hidden Bednář lookout, which is about 15 minutes to go through the woods.
The Máj lookout is located about 35 kilometers south of Prague. After you park your car in Teletín, you can take the 15 minutes easy walk towards here.