Well, I used to have a paper round in London... so it's probably a bit different to here. For one thing, it was flat land and all the houses/flats were close together, so it only took around an hour. I also did it in the morning. Getting up at 6:30am when it's foggy/raining/bloody freezing and pitch black outside wasn't great. The pay was also kinda shit, at $27.50/week for 5hrs work. Then again, I was 12 when I started, did it for 2yrs, so they could afford to pay me shit.
Anyway, I don't reccommend it unless you have a dog you could walk at the same time and get your parents/neighbour to pay you for that as well. Or, if you count this as your exercise/sport quota as well as work. I guess it would also depend on the route - I would never do somewhere hilly.