I did the walk from Es Cana to Mastella last year.
It was a fair old stroll but very very pretty.
Sorry, no map with me at the moment so can't recall the actual route but very roughly we did a coastal bit for maybe three quarters of the journey and then seemed to drift inland little for the last half hour.
We went past lots of agricultural land, trees and lovely villas. I was hungry and picking various bits of fruit off the trees. No idea what the hell I was eating but it went down very well.
Mastella is lovely. It was raining but hot the day we went so were essentially on our own. The swimming is nice but you have to do a bit of ballet dancing around ferns, rocks etc on the sea floor.
PS - don't forget the restaurant round to the left of the beach. I think you have to book in advance but its very highly rated.