I doubt that you've seen any bays between Dalaman and Gocek as the D400 doesn't run close to the coast there.
The 2 main bays after Gocek are Günlüklü and Katrancı, both of which are signposted and easily accessible as they have campsites. You can also get to Inlice beach by turning right immediately after coming out of the bends after Gocek. If you're really adventurous, and have a 4x4, there are several forest tracks you can use to get to other sites along that stretch of coast.