The Towpath Trail is a circular walk of about 3km, it takes you along the Wareham Causeway, through Ridge, past Redcliff and then back along the Towpath to Wareham. There are plenty of places to park in Wareham but the Quay is the closest (There is is a small fee and you can't park there on Saturdays.)
This is one of my favorite parts of the walk, it's a very scenic place and I have always wanted to place a geocache here. The are some new information boards in this area which are very interesting and worth keeping your eyes peeled for.