Start with a mole hill, and exaggerate from there.
Ok but seriously. So I have this wacky idea: you could try using cloth.
I tried it myself; set some semi-random poly cones at different heights (pointy end up of course) as collision objects to form your peaks, and dropped a high-res poly plane cloth object over them. Naturally the topology sucks, but it actually produced some pretty decent bowls and ridges, with minimal effort. I also had a collision ground plane set. This worked pretty well, as this caused the ridges to extend around the base of the mountain in a pleasant way.
There were a few trouble spots where the cloth started to fold, but nothing sculpt->smoothness tool couldn't fix. And changing the cloth attributes and resolution could be used to almost dynamically affect the sagginess of the bowls, the bluntness of the ridges, etc. until you get a look you like.
While it's an amateur solution, you might still want to play with it for a minute. It could provide a starting point. Maybe use cloth to form your initial structure, render it out as a depth pass to texturize and detail in photoshop, and bring back as a height map...