Nigel: Not sure if you meant just LJ to answer about the bikes, but I'll throw this in:
In the late 40's, early 50's I had a bike that was bought from Western Auto. I think my Grandpa bought it. Yep, we clipped playing cards to the fender braces so that they would flap on the spokes making that "motorcycle sound". We also slipped the old bottle caps between the spokes and slid them down toward the hub. You'd try to get enough to make circles of different colors all the way around the hub. I decorated the seat, after the bike got older, with a "wood burning kit". Remember those?
The hill, in town that I remember (we moved in in 1956 when I was 12) was what was called Main Street hill. It was west of Green street, before 8th street was extended all the way through to Hershey. It was black top and steep with a ravine on one side, just before 3rd street cut in. One of my friends lost it going down that hill, with me riding along by his side. I think his chain broke. He shot off over the edge into the trees and ravine. I thought he had killed himself. But just had the normal painful kid injuries that you nursed yourself - afraid the parents would holler about if they knew how we got them.
Sorry to but in, but it's fun remembering.