No town is listed nearby, and that is the point: this is a country of long distances, of gravel plains, salt crusts and distant ranges, where a few hundred people live around a spring and a stand of poplars. Garmsar, on the northern side, is the nearest place with regular services that I can name with confidence.
Qasr means fortress or palace in Persian, and in a landscape like this the word usually points to a fortified building that served travellers, a caravanserai or a small stronghold set at a day's journey from the next one. For centuries the road along the edge of the Dasht-e Kavir, the Great Salt Desert, carried silk, spices and pilgrims, and the caravan stops were built of mud brick and baked clay, with thick walls, a single gate and rooms around a courtyard for animals and people.
Riding here is about heat and distance. In summer the temperature on the plain climbs well past forty degrees, the tarmac is soft in the afternoon and the wind carries fine dust, so start before dawn and rest in the middle of the day. Winters are cold, with frost at night. Spring is the kindest season, when the hills are briefly green and the wild tulips and poppies bloom on the slopes. Roads are generally straight and good along the main highway, but side tracks are sandy and unmarked.
Do not count on services off the main road. Carry water, fill the tank at every opportunity, and keep some food with you. Tea is the universal courtesy, and a driver or farmer who stops to talk will often offer a glass from a flask. Check current travel advice and permit conditions for Iran before planning, and make sure your papers and insurance are in order, as the rules for foreign motorcyclists are strict. Bring a map and a downloaded route, because the signal is unreliable.