Na Pali is on the north side of Kauai. If you think you can drive to the Na Pali coast and beaches you're wrong. It's a long 2 mile hike to Hanakapi'i and then longer on to Kalalau from Ke'e Beach. When you do reach the beach you can see caves, rough surf, and beautiful views of the mountains.
When I hiked there, I went in the summer because the trail gets too wet in the winter. There are narrow parts of the trail that get slippery. If you go in the winter, the water is rougher than usual so you can't swim in the ocean. There are also strong currents and rip tides.
The only other way that you can get to Na Pali is on a kayak or zodiac or a boat. There are no buildings or houses or stores. Usually there are only couples or families hiking. You can camp along the trail and picnic on the white sand beach.
If you stood at the beginning of the trail, you would see mountains stretching into the ocean like they are overlapping each other. In between each point there are valleys. There are really many beaches that are on the Na Pali coast. The first one is Hanakapi'ai, followed by Kalalau, then Honopu, then Nu'alolo Kai, and lastly Miloli'i.
There are many sources of water along the trail. You can see waterfalls and rivers. Before you get to Hanakapi'ai Beach, you cross over the Hanakapi'ai stream many times. You aren't really supposed to drink the water but some people do and some of them even shower in the waterfalls.