Startup Idea: Treadmill Journey Tracker

Startup idea to develop a software that allows users to simulate walking from one city to another on a treadmill, with a feature to track progress on a map and outline an actual route along highways.

This is more of a point of leisure, but I feel that there is definitely an opportunity within it. I recently started using a treadmill and decided that I needed a goal. I decided that I would simulate walking from one city to another (for example, Detroit to New York). I would like to be able to track my progress on a map, developing a route for this over time until eventually I would have gotten there. After some searching I have found that there is not a program designed to do this. While I could simply calculate the distance between the two, it wouldn't be as satisfying and likely would be "as the crow flies" instead of an actual route along highways and such.