Gonna do most of this stuff in phase 4 since the cap will obviously prevent progressing in the story too far:

1) Sort out inventory
2) Do up to the level 20 class quests for ARC/CNJ/THM (screw the other classes, I wouldn't want to play them anymore anyway!)
3) Start off ACN, and try to hit 20 before the end of the test
4) Once I hit 20 on ACN I may start my DoL/H class quests to get them out of the way