Visited in July 2018 after Kharkhorin (Orkhon Valley WHS) in Mongolia, so I can compare and have a continuity in the history of Mongol Empire.
First of all, there's no public transport connecting the site to the nearest city ZhengLanQi. The best option is to negotiate price with the taxis frequently parked in front of the bus terminal. The distance is about 20 minutes drive on good paved road. I talked to the taxi driver and found out that most of the artifacts and graves were looted openly before there were any laws to protect in 1990s. So do prepare yourself with some readings or hire a guide, or else you will just see a vast field with mounds, walls and ruins.
The entrance fee is quite cheap at CNY40 compare to other major tourist sites or WHS in China. Then you have to choose to take a buggy, rent a bicycle or walk to the core zone like I did. At the time I visited in July, there are a lot of beautiful flowers along the way so I just walked and imagined the ancient life in the city.
There are two gates in straight line after you walk pass the vast steppe. Imagine how the Mongols on horses enter the city after each victory in war. There is a platform in the middle of the city where the ceremonial temple used to be. And finally the elevated place where Kublai Khan's palace used to be situated. It's the place where he greeted Marco Polo and you can see the whole city structure from this place.
Most of the ruins and bricks at the site are in Ming era, but there's an original Yuan's era brick wall where the archaeologists cleared in 2012. But you can see that it's worn out fast after exposed to the air and bad weather.
All in all, it's not an eye-catching site if you don't know the history behind it. Does it worth the effort to go there? I will give a 3.5/10.