The full 87 miles of the official Ridgeway National Trail can easily be divided into shorter segments, depending on time available. It can be cut more or less in half, by deciding to walk only the older, original western section, which passes all the great prehistoric sites. Day hikes, and half-days centered on the Uffington White Horse, or Wayland’s Smithy, or the Avebury Stone Circles, can easily be devised by studying the map. The trail’s excellent Web site (www.nationaltrail.co.uk/ridgeway) is full of advice, and possibilities for accommodations and meals.