Ganbold, a local herdsman, runs one of the more popular guest ger outfits. You'll see his home to your left (east) as you approach the dunes from the north (which is the way most people come). Accommodation in the guest gers is basic, and Ganbold doesn't speak English, but this is a reliable place.
Camel rides cost about T30,000 per day, plus T20,000 for a guide and his camel. It's only about a 2km walk from the dunes, but at least a 12km hike northeast of the tallest dunes.