
I read recently about alternative reality games,  you probably know about them already. They are puzzles that take place  in reality but have a set of modern parameters for the followers to  complete in able to get to the next piece. One involved solving a puzzle  which released an email with GPS and time co ordinates in it, if you  went to that place at that time then you would see a plane spiralling a  message into the sky which would solve that part, and then give you  vital information to solve the next riddle. 
I am not sure you would get me jetting off to the requested GPS, but I  love the ideas, the chase and the reward being as simple as I've done  it.
The above image is from a tale that takes place near Porlock Somerset.  To read the tale you have to journey to Porlock Weir, with GPS enabled  device. (Possibly your mobile phone - fully charged!) The tale happens  over the walk, as you journey chapters are revealed till at last the  story is complete and you are at your destination. Of course you could  walk that way without any device, and it would still be worth it, as the  woods around here are stupendous. But having the story along aswell  takes you to another place. It's a little like finding a hidden  sculpture deep in a forest clearing. Someone took time to make, time to  craft and then site all those years ago. Was that done just for you? Why  did you see it? Was it the light, the hour, the angle, all coming  together like an eclipse, after all those years hidden in the  undergrowth, it can make you feel very privileged.
The story walks were created in this way, there was no big puzzle beyond  the tales themselves, and you can't read the tales without walking the  trail. Each chapter reveals the next location, so you don't know where  you are really going at all!
You said tales, yes there are some other walks hidden in the hills  around here too, and who knows I may put a code in at the end of each.  Some kind of cypher to unpick a hidden web page with a special tale to  download, revealing a clandestine destination only for those with mind  and heart ready to venture into the inner circle!