QR version of geo-caching

Essentially I wish to create a geocaching-style game by using QR stickers instead of boxes. Will require a website with member login/registration (so members can have simple profiles to gain points by finding the QR codes). I will be making QR codes in 4 difficulties indicated by the colour of the code (green-easy-1point, orange-intermediate-2points, red-difficult-3points and black-special-5points). To find these users must be able to access a simple map (preferably linked to google maps over apple/bing etc. that shows the locations of the QR codes AND their colour (difficulty/points). I have been using a squarespace trial just to check the system of scanning a QR code leading to a webpage that says congrats / how many points it was worth based on the colour. on the full site however this must of course be a single use page so members can't repeatedly score from the same QR code and it must also add the appropriate number of points to their profile. If we could talk about how to add locations / codes to the site once its complete this would allow me to be independent in the site's maintenance. I'm fairly good with photoshop to the point that I'd be happy creating my own icons / logo etc. Members profiles / point systems / map integration I have no experience with. Many thanks, Robin.