When you are talking about the Silk Road http://www.turismocinese.it/itinerari/la-via-della-seta/ we refer to the road that allowed large western empires touching China, through Central Asia. Take that route (which links Xi’an with Istanbul), moving from east to west. Silk started all from China. Over the centuries, the path followed by the merchants has changed, so it is difficult to identify a single itinerary. Whichever route you decide to do, you will need to follow a route of about 6000 km, devoting several months of your life to the gift of that emotion, the encounter with the civilizations that you find along the way. Geography and languages, food and markets, are your chance for an epic journey.
Do not forget one thing: the eastern end of the Silk Road is a funnel. China we know today is a vast territory, but for thousands of years it has failed to expand westward. The difficulty was due to the Tibetan plateau and the Gobi desert. The opening of a passage in the Gansu Corridor, has changed the business expansion opportunities. Xi’an (city from which to travel to the west), is situated at the eastern end of the corridor. With the growth of Islam trips were interrupted for centuries. After the capture of Constantinople, the Turks closed the doors to Western travelers.
The current paths? The first comes under the Caspian Sea. From Xi’an you get to Kashgar (one of the major hubs of the Silk Road), from where you can reach Pakistan and Afghanistan, Tajikistan, Kyrgyzstan and Kazhakstan. You can go to Uzbekistan and Turkmenistan to Iran. If you have little time available, you can use bus or train, linking Tehran to Istanbul. The second route passes through Kazakhstan, from where you can reach Aktau (the city from where a ferry crosses the Caspian Sea). Landed in Azerbaijan can reach Armenia or Georgia, and arrived in Turkey waiting for you in Istanbul. http://www.cnto.org/?s=SILK+ROAD
You can see more on MeetingBenches, looking for http://meetingbenches.com/2016/11/landscapes-soul-along-silk-road/