Please see my travelogue on my Muker page for the hike my parents and I did in November 2006! We did the Muker-Keld-Muker Circular Walk and following the River Swale.
There are lots of alternatives for those who want to walk in the Dales. The most famous paths to go through the park are the Coast to Coast walk, and the Pennine Way. The Coast to Coast walk enters Yorkshire from Cumbria up in Swaledale in the north and you follow that dale to Richmond at its lower end. The Pennine Way follows the Pennine Hills from Derbyshire into Yorkshire further west, and up along the Malhamdale area it then enters Wensleydale at Hawes before continuing towards County Durham. Reeth and Hawes are therefore great places to meet other walkers but any village will have footpaths with views that make you want to stay forever :) The National Park visitor centres are good places to start as they sell books and maps (and can tell you about public rights of access) but if you want to prepare in advance for one of the long walks, check the link on the front page or the links below. There is also the Ramblers association to contact for their local branches: http://www.ramblers.org.uk/
Equipment: Good (walked in) boots, rain gear, warm but breething clothes, water, maps...
Oh yes, extreme sports! hahaha!!!
There is a little book which describes a pub walk in the Yorkshire Dales. You walk from pub to pub, sleep and eat (and drink!) there.
Our friend and my beloved will do this walk someday. Mostly because the furthest pub is only 15 miles from the friend's home so the wife can pick them up anytime if the going gets too tough.
Die-hard guys indeed....
Equipment: Look in a local tourist office or bookstore for the book.