As might be expected, because the Silk Road is such an important historical and cultural phenomenon, ours is not the first online resource to feature it.
UNESCO, The United Nations Education, Scientific, and Cultural Organization, has declared part of the Silk Road a World Heritage Site. Their website is here, while a Wikipedia page dedicated to it is here.
ESRI, the company that makes ArcGIS mapping software, has produced dozens of free online map-based geographical classroom activities called GeoInquiries. Their Silk Road GeoInquiry can be found here. The map itself is located here. Click on "Content" and you will be able to turn individual map layers on and off. This particular activity could be used in the classroom at any level from Middle School to college.