How far was it along the Silk Road from Chang'an to Dunhuang? To Antioch?

The Silk Route was the most important international route in the ancient world. It connected the China (East) with the Mediterranean (west). It is almost 7000 miles long.

There are multiple routes from Chang'an (長安) to Dunhuang (敦煌) along the silk road. The distance between Chang'an to Duhuang is about 1000 miles and to Antioch about 5000 miles and to Rome, it's 7000 miles.