If you really fancy going out and about why not try walking through the country with a purpose. And seeing that the walking through Britain from Land’s End to John O’Groats might be a bit overambitious, not to say overdone, you could follow in the footsteps of Hilda and Graham Heap who trailed along the Prime Meridian and wrote a book about it. Well, four books to be precise. The guides use ordnance survey maps for easy route finding and are full of information about the places you might visit and stay at along the way. Good access by public transport makes it convenient to do the walks in sections.
The Greenwich Meridian Trail (GMT Walk) is a long-distance walk along the line of the Prime Meridian.
The walk starts at the splendid monument to King George V at Peacehaven in East Sussex and ends, 273 miles later, on the coast at Sand le Mere in East Yorkshire. The walk is divided into four parts, each explained by a separate guidebook. You can find out more about Hilda and Graham and their books here: http://www.greenwichmeridiantrail.co.uk