I have friends from Ohio looking to move to the Denver/Boulder area...Louisville specifically

Many streets in Louisville fit that description. There are some great areas near Cottonwood Park (check out Caledonia Circle, or the home at the end of Short that is available now). I'm sure their realtor will point them in excellent directions. Just steer clear of some of the busier through streets, and they should be fine (Centennial, for example, can have a decent amount of traffic, although it doesn't seem like it's a major road). Feel free to contact me for more specifics, but I don't want to cross lines with their realtor.