I believe:
Level 1: 3 days
Level 2-9: 14 days
Level 10+: Level*2=Days before deletion
For example, a level 10 player would get 20 days, while a level 25 player would get 50 days.
The vacation mode would be for people level 10+, and would be able to extend 14 days past the normal deletion time.
There should also be a "Delete my account" button.