No restrictions, although they only reimburse you for fuel at like half price or something like that. So we just staged our trips as out and backs where we wouldnt need any fuel. Out and backs to the Keys, Bahamas, South Georgia and all over Florida are attainable on one tank.

EDIT: They will allow you to take the plane for extended trips as long as the schedule for it is clear. They fly a lot for training during the day and usually give them to time builders at night (from 6pm-6am).