Getting a friend to 50?

Hey, I've got a friend who is hopping back in FF during the free week, at the moment he is level 30-ish and I would like to know a way to get him to level 50 nice and quick, so that he can experience the endgame dungeons and the like. What's the best way to level him up quickly?

I doubt you'll manage to gain 20 levels in a weekend, but if you can get a 4 man team together working on the highest level dungeons that your friend can tackle would probably do it.

Hakkuke Manor until he's level 32
Brayfox Longstop from 32-35
The Sunken Temple of Qarn from 35-38
Cutters Cry from 38-44
Sezemel Darkhold from 44-50.

The first two are story related, so you need to access them via the main quest line. The last three are optional so can be accessed without having to do all the story.