I think that now that elves are traveling in space, they have formalized a way that the guidebook can be automatically updated by the travelers themselves. So if one now has the location of a place, they all have it. It would be a sensible way to do it. The Telzee route was supposed to be to get an elf to a place he or she had never been, that had yet to be added to the guidebook. Before Max and company started roaming the stars, elves didn't exactly go to a lot of new places not in the guidebook. Their magical routes had been fairly standardized. That has changed now, definitely!
Anyway, Max was able to get to Keerby by normal means, because Keerby was already there,
What Casper can teach the others remains to be seen. I have only a general idea of what he can do just now, myself!
Thanks for the nice comment.