For the longest time, Zwifters have requested the ability to create your own routes and ride your own routes. Road Captain was created by a Zwifter who wanted to create a solution for these Zwifters. The program is currently available to download on GitHub for both Mac and PC.
What it does
Road Captain allows you to use an assortment of starting points throughout Zwift to create your own custom routes. These routes can go pretty much anywhere in the game, as long as there is an option to turn in the direction you wish to go on. Road Captain has two separate programs. One for building routes, and one for running the routes. When you first open up the application, you will see green segments. These are the places that you can start your routes. After choosing a starting point, you can then select the segments that you would like to use in your route. When you are done, just click save. The route will then be saved to your Road Captain routes!
In order to ride the route that you have created, you will need to open the runner app. Once you open the app, a new window will open so that you can log into your Zwift account. This will allow Road Captain to connect to your account and the application. You will then be able to select the route that you would like to ride. It will then ask you to open up Zwift and navigate to the world where your route is. Once you are in game, the Road Captain window will display a number of different statistics. These will include: Distance covered, total distance, ascent covered, ascent total, progress bar, segment details, and more.
For a video of how to build a route, see this video provided by the creator: https://www.youtube.com/watch?v=gMUGyPEI96Q.
A full write up of everything you need to know about the program can be found here: https://github.com/sandermvanvliet/RoadCaptain.