maybe we can use an item like a key .When they get a key they can go into a room(mystcraft age) ,only when they clear the room they will get the next item .To make it harder on us :D
One question ,will the silver tree from thuamcraft spawn in high veast area that human made?because if it is we can make the silver log one of the objective(or path way atleast)
with 3.1.2 coming out you can make the player enter the book spawn on a pleasure plate and use command block to turn their gamemode to adventure and let's them find their way out.
if i'm correct,mystcraft allowed you to create the new age which is a new world .So if they add mystcraft into the mod pack ,people can travel out of the map boundary?
(sorry for bad gramma and spelling)