I started walking a few years ago when I realised that I needed to find some (any) exercise that I could do and not give up after a few weeks. Having the spectre of trekking to Everest Base Camp also provided a modicum of motivation to get my butt into gear. So my plan was to find something I could do easily, anywhere and, if at all possible, didn't feel like exercise. If you are map reading, finding out about local sights, or even better having a good chat with a mate then your legs seem to keep moving without having to think about it - hurray!
Right now, I'm walking the Grand Union Canal with Mum and we're also thinking of tackling the Icknield Way too (see lessons from the Wolds Way!)