This is not a fully detailed map of the area. If you want to walk here get the 4 Explorer maps. If you want every tiny lane to drive down get the 4 Landranger maps. if you want an introduction to the area and the whole area on one sheet for less than a fiver, this is the one for you! It's got so much info on it too: town maps, an index of place names, lots of touristy places like country parks and craft centres, National and Regional cycle routes, picnic places, car parks, pubs, etc, etc. It also shows nearly all the roads you will need, including most of the byways and ALL the towns, villages and hamlets.
It's one of the products the OS doesn't seem to value, as it's hard to find in the shops and not even well trumpeted on their website, but if you're visiting the area for a week or so, it's cheap and invaluable.
I live here, and I have a full set of the Explorer and Landranger Maps, but the one that's always in the car is this one.