This is an alternate approach to the dunes.

The downside is that it's a very long walk to and from the dunes. Bring a ton of water, be prepared to walk 30min to an hour.

The upside is that you get mostly untracked dunes when you get there, and many fewer people. Also there's some potentially interesting stuff along the way.

The walk to the dunes is generally pretty easy, as it's very flat. Unless there's a lot of water in the valley, then it may be too muddy.