Greetings!
Your project seems straightforward - an app that takes GPS coordinates to track actual running/walking data, accumulating it in a database, and then showing progress through a "virtual" tour of some sort. On top of that, there would be a "friend" system, that could potentially function through Facebook, or Google, though perhaps will be more easily managed internally.
I am a highly experienced C/C++ programmer specialized in 3d graphics, games, and educational software for more than 15 years. I currently focus on apps and games for mobile devices and can deliver cross-platform solutions for Android, iOS, Windows, OSX, and even Tizen.
I use the Marmalade C++ SDK for rapid development and deployment to all smart phone platforms. I find this tool to be the best way to solve almost any problem.
I am newbie to freelancer.com, so I'm not sure how this all works. Sorry if my rank is low!
Hope to hear from you soon.
Best regards,
John Klima