There is an Engraved Desk on the second floor of the Library. Go to the South Wing Catalog, then through the teleporter at ( 332, 15, 173 ) Copy/waypoint 332, 15, 173 to the Crafters' Gallery.
You must replace your current mount with the illusion, then Summon Mount. (If it does not want to go into your mount window, you could have maxed your number of mounts. Trying removing a mount and putting this in its place and then equip it.)
Take the teleporter at ( 143, -179, -820 ) Copy/waypoint 143, -179, -820 to Crosswind Isle. Take the teleporter at ( 384, 181, -250 ) Copy/waypoint 384, 181, -250 to The Aerie and travel to ( 1228, 279, -43 ) Copy/waypoint 1228, 279, -43
Take the teleporter at ( -516, 357, -429 ) Copy/waypoint -516, 357, -429 to retrace your path back to Recipes for Adventure at ( 454, -202, -1432 ) Copy/waypoint 454, -202, -1432 in The Windglades, or evac.