Horse Riding - Colne Valley Regional Park. Horse Riding Riding is very popular in the Colne Valley. There are a variety of routes and riding is available in the country parks. A long distance ride of 45 miles, Heron's Way, starts at Willetts Lane off the A412 at Denham and connects with Swan's Way at Bledlow. Days Out Guide - London attractions with train tickets. UK Holidays and Leisure Guide.