The Nashua River Rail Trail runs from Ayer, Massachusetts, to Dunstable, Massachusetts. It runs along an abandoned rail bed that was paved in the years 2001 and 2002.
In 2000, before the paving began, I rode the trail on my mountain bike and took a series of photos. In 2002, I made the same trip and tried to take photos from (roughly) the same places along the way--using the same cheap digital camera.
You can view the results. Note that you can switch back and forth between the 2000 and 2002 views using the options between the Prev and Next buttons. Also note that all mileages are approximate.
Depending on your browser and operating system, you might be able
to use accelerator keys for Next
By the way, the town of Pepperell has a map of the rail trail available online.