The Pewsey Downs, just South of the 5000 year-old stone circle of Avebury in Wiltshire and its neighbour the ancient Silbury Hill are recommended as a real treat. They could qualify as the most beautiful place in England, and certainly Southern England, because of their ancient and unusual shapes and rich heritage.
There are not many B&Bs in the area, but one suitable one might be the New Inn at Winterbourne Monkton (google it), which can accommodate between 6 and 10 people at time of writing (May 2008). The area is probably best seen by doing round walks and is only easily accessible by car or on foot, but not by railway.
The Pewsey Downs are the site of unusual flora and fauna, including rare butterflies in September. The easiest paths in the area are found by following the White Horse Trail, all of which is clearly marked on OS maps.
Avebury is a small village inside 3 concentric rings of stones, similar to the nearby Stonehendge. Within walking distance is the start of the Ridgeway Long Distance Path along a grassy ridge, and an unexplained burial mound (Silbury Hill, a stone age, man made, hill). The village itself has a lovely church and a great pub that caters to tourists, kids dressed as Harry Potter, bikers and druids.
The area is easily reached by car from London. Public transport is harder, bus from Swindon (train from Paddington), or a day's walk from Pewsey (train from Paddington). Both are outside the Network Card area.
Ideas for Short Weekend Trips away from London, and Walking holidays in Europe