The entrance to the Gobi desert is within easy reach. It is an easy-to-reach destination, whether you are coming from China or Ulaanbaatar, the capital.
My suggestion:
Book a hotel if you have just crossed the border between China and Mongolia - the train to Zamyn Ud (in the south of Mongolia) arrives at Saynshand at one o'clock in the morning! And there are not many taxis!
Summary:
Don't come here for the town! It is a 'desert town' with four big main roads, and that's all. I thought of making this my starting point for crossing the desert but I was strongly advised against it! People come to Saynshand for what there is around it - the holy site of Shambala, the Ikh Nartiin Chuluu nature reserve and the Suikhent Petrified Forest (further away).
The outskirts of the town are completely desert-like, and from time to time you spot the yurts of nomads, camels, herds of goats - all very exotic! The town itself gives you a good glimpse of what day-to-day life is like in the desert, but it does not take long to see it and it lacks any kind of charm.
I stayed there for two days, enough time for one excursion per day, and then I continued on my travels. You could do the same, or simply pass straight by!