Build me an adventure race App -- 2

Hey there I am looking at creating an adventure race/treasure hunting in a local area. But would like an app built which would allow contestants ability to track down locations. Once they come within 15m or so of a GPS destination they then will get access to another destination or clue. I would also like their GPS to work like a compass and point them to the next destination. So basically directing them where to go (even a distance meter would be great, counting down how far they have to travel) once they arrive at their destination they can access information and a video or something? can anyone help?