Did you find the campsite area on the most north eastern beach (tent, couple chests, blanket on the sand, couple sets of poles stood up to hang fish), not too far from a teleporter and the door to Laiken's Study? He should be wandering around there somewhere.
If you have the Developer's Cut release of the game, you can load the save in the Developer Mode version, hit F11 to open the cheat window, and use the GotoCharcter function (on the right side) to teleport to Allan.