Have you thought about taking a trip on England's waterways?
If you are young at heart, and love a low-key adventure you cannot really do better than hiring your own narrow boat and cruising gently down the Avon from Stratford to Tewkesbury. The trip can be completed confortably in 6 days. The river scenery is......constant eye candy. There are picturesque towns to explore along the way such as Bidford, Evesham and Pershore. No prior knowledge of handling a narrow boat is necessary, me, my wife and two friends, all Americans in our 60's had a lot of fun negotiating the modest number of locks we encountered in the 80-mile round trip. And starting and finishing in Stratford is the icing on the cake (we even managed to see an RSC production on the last night).
I am sure that there are plenty of reputable firms that will hire you a boat. We used Valley Cruises www.valleycruises.co.uk and found them wonderfully helpful. Their boat was immaculate, and couldn't have been better equipped.
We cruised in september when the crowds were lighter but the weather was still pleasant. There is nothing better than sitting in the stern of your narrow boat, eating a bacon and egg sandwich as the early morning sun begins to get warm.
I noticed that there were some earlier postings on the topic of canal/river holidays but none in the last year or so. Having just come back from a wonderful trip I wanted to let people know what a great vacation option this is.