The biggest question is your driving record. If it's clean, and you perform well, expect to get some of the more cushy drop-off routes in your area.
Oh, sorry; maybe I wasn't clear enough with my explanation of the position. I'd be inside what is basically a stuffy warehouse, packing up the trucks with boxes (or otherwise, unloading them, possibly onto a conveyor belt). I'm told that the enormous trailers must be loaded/unloaded within 45 minutes each; as of now, I'm still unsure about exactly how
much of a challenge that will be. All of the UPS drivers/delivery people, however, had to start as package handlers.
It depends on how many people are helping you. When I worked at a retail store, I was on the dock crew and we had until 6 AM to unload the truck that came in at 4:30 AM. It was me, one other person, and a 52' trailer. We usually got it unloaded by 6:15 AM at the latest, and that was with very large items you wouldn't encounter in a UPS warehouse.