Griffin ride is used to get to MOD.
To be able to buy the ticket, you are reqired to get right faction first.
Go to Hagall, left of the entrance to the Hagall town, there is a dwarf lady. She will let you buy a ticket for the griffin ride if you have good faction with dwarfs.
How do you get faction? Go outside of Hagall, there are mobs that looks like humans near the tree houses. Kill them for faction. If you have good group going, you can get faction in a hour or so.
you do not have to get in griffin ride to get to MOD. You can run and then swim there. Using /map comes in handy.
However, the griffin ride does make things easier to get to MOD though. =P