Here is how I paint pale sandstone. I find this recipe gives a nice neutral tone that works well for bases, and doesn't detract from the mini.

1. Basecoat with Rakarth Flesh .
2. Wash all over with :Citadel/AgraxEarthshade.
3. Drybrush the stone with a 1:1 mix of Rakarth Flesh and Pallid Wych Flesh . Make this quite a heavy drybrush, so that it leaves a little texture on everything but the recesses.
4. Edge highlight everything with a this line of Pallid Wych Flesh .
5. On corners and sharp curves, ad small highlights of Pallid Wych Flesh , mixed 1:1 with a pure white.
6. Add spot highlights of a pure white to corners and points where light would hit. I like
   to use Dead White .

Dirt Base

1. Basecoat with Steel Legion Drab .
2. Wash all over with Agrax Earthshade , thinned with an equal amount of Lahmian Medium .
3. Drybrush with Karak Stone .
4. Lightly drybrush with Screaming Skull .
5. Add occasional dots of Pallid Wych Flesh to larger grains and in odd places. This helps the dirt look less uniform.