Where can I find a picture of the route the two men traveled?the two men are Montresor and Fortunado.
I couldn't find anything on the entire path they walked. This may be due, in part, becuase the story was set in an undisclosed location. Below are some links that may be of use though.
This link shows a picture of Fortunado chained to the wall as well as Montressor preparing for the murder. It does an excellent job conveying the different story elements through art.
This link expresses the despair of Fortunado, the vacancy of emotion in Montressor, and the environment of catacombs.
The following couple of links offer more artistic representations of the scene and can be used to interpret as you see fit.
I do not think there is a specific website or image for the route that they traveled. The poem states that the catacombs were modeled after Paris. However most cities at the time had unused catacombs from days gone by. Any major city in Europe and in America would have had a hidden world underground.