There is a wonderful Yogi Bear Campground in the hills near Larkspur, Colorady.
Surrounded by countryside, there's also a big ol' mainline of the Burlington Northern Santa Fe Railroad running right in front of the campground. It seems like hundreds of coal and freight trains strain to carry the load up the long hill outta Denver and Castle Rock southbound to New Mexico and Texas day and night. It's a railroad fan's heaven. The trains barely seem able to make the hill and it's a blast to stand beside the track and watch them trains sloooowly roll by.
Here's some pictures taken by rail fans from RailPictures.net.