I'll be picking up my third party prepaid Avis in mid-May, around 3:00 in the afternoon. Unfortunately I cannot risk trying to connect the rental to my Avis Preferred account, due to reports I have seen about losing a discount if that is done. So my plan is just to head for the main counter and hope for the best. My guess is that 3:00 is a little early to be completely out of cars; if I have to wait around while incoming cars are cleaned/washed/whatever, that's fine assuming I actually do get one.