I concur with Baftap. 28 can be kind of ***** tonk. 6A is beautiful. There are also some beautiful quiet interior roads. The former rail right-of-way trail for bikes and peds goes all the way to P-Town as well.

I don't don't know the routes in enough detail to map it out. I once successfully used the google maps bike routing feature to map a Sagamore to New Seabury route. As you hone in on a route, maybe you could post a link to it here for added input.