Visited Shakpak-Ata as a day tour from Aktau - about two-and-a-half hours each way of riding on roads that start decent and fizzle out into mere suggestions. Really foggy day, but the fog cleared just long enough for us to visit the mosque. Personally, seems auspicious to me.

The site itself consists of the mausoleum of Khazret Yerzhan, a 20th-century mausoleum dedicated to a local religious figure, where we parked before walking approximately 500 metres to the cave entrance and necropolis. Would have loved to visit the necropolis, but there was a fierce-looking dog hanging out there, so thought it was best to steer clear. The actual mosque entrance is fenced off, so we could visit without worrying the dog would follow us.

The mosque itself is quite remarkable - the cave offers natural pillars framing the entrance to the prayer room and the wudu areas; the interior is rather humble, but features pilasters with fluted capitals. The mihrab is carved into the cave on one side of the prayer hall, with smaller rooms beside it (filled with geckos). An exit in the back leads to a staircase going above the cave, with views of the surrounding landscape. Most interesting were the graffiti and petroglyphs all over the site, left by generations of pilgrims to the site.

I haven't visited the other sites that form part of the nomination, but based on this one, I would recommend it for inclusion.