Hi Ruth,
Kingswear to Brixham is a cracking walk. There are a few steep climbs but it is worth the effort.
From Churston you can get the No 12 bus to Brixham and from there one of several buses to Kingswear. There are not many places for refreshment along the route so take plenty of water with you!
Unfortunately the bus route cuts across the headland so it is not easy to cut the walk down - but there several nice coves along the route that are not usually too busy that are perfect for a halfway picnic.
You could also go the other way - towards Torquay. This is more of an urban coastal walk but still quite surprising as long as you do not mind walking on tarmac - plenty of refreshment on this walk!