Treadmills suck, but they are good for hill work, especially if you don't have any hills around.
Hmmm... I don't have access to a dreadmill (without buying a gym membership or something). It's definitely something to keep in mind though. I have a friend who will only run on a treadmill during Florida summers.
Not a lot of stairs around here either. The stands at a football field would probably work, but I think they are behind a locked gate.
45 minutes to the nearest beach. I wonder if the intent of having hill repeats in the workout is to have the extra resistance from a hill, or to focus on the change in form from running hills.
I was still struggling with this over 4 years later. I just ordered a NordicTrack Incline Trainer: it goes up to 40% grade. (Unfortunately it's still a treadmill i.e. not a real hill.)