Hengistbury Head is in the Borough of Bournemouth, but is included here because is closest to Christchurch and a beautiful place for residents and tourists to visit. It is easily accessible via the ferry at Mudeford, a journey of about five minutes. View their website to see some excellent videos, and lots more information about it, including sailing times. There is a large car park on the quay near the ferry, but be aware that this gets very busy in summer. You can also drive there, and there is a bus service and another ferry. Full details are here. When you are there, you can even ride on the land train, which pootles along very frequently and is a great way to get some fresh air without tiring the legs!
Click the map below to see their excellent website.
If you go by ferry there is a very pleasant cafe and a little gift shop:
Here is a Daily Mail article about the famous beach huts, which are the most expensive in the country. The one in the article was sold for £280,000. There are lots of them, and just a few are shown in the picture below, taken from the top of the Head on a misty day,
You can stroll along the sand spit and find wilder places, but still very close to civilisation.