What I can tell you is what a caravanserai was, because the answer explains the place. Along the Silk Road, travellers needed to eat, sleep and water their animals every day or two, and rulers and merchants built fortified inns at intervals along the way, with thick walls, a single gate, a central courtyard and small rooms around the edge for people, with stables and storerooms.
The desert here is vast, flat and quiet, with low dunes, saltbush, and in spring a thin carpet of green and red poppies that disappears by summer. The ruins that survive are made of mud brick or baked brick, and they weather quickly, so what stands today may be a fraction of the original. The ancient oasis city of Merv, a World Heritage site with the mausoleum of Sultan Sanjar, lies not far to the west, and gives an idea of the scale of the culture that built roads and inns across this country.
Anyone thinking of riding here needs to prepare carefully. Turkmenistan has strict entry requirements, visas are difficult to obtain, and independent travel is normally limited, with guides, itineraries and transit permits required for foreign visitors. Rules about motorcycles, border crossings and the use of cameras are subject to change, so check them with a specialist agency. Fuel is cheap, but supply can be uneven, and distances between towns are large. Heat in summer is extreme, often above forty degrees, so spring and autumn are the best seasons, and winter nights can be cold.
There is no town nearby that I can name with confidence, so plan to carry fuel, water, food and spares for the whole day. If you do get there, take it slowly, drink a lot, and let the silence of the place do its work.