Gavin Wheeler wrote:

But wouldn't it be lovely to have a bus service linking Swansea,
Middleton, Aberglasney and Carmarthen? I haven't looked at a map in
detail to see if that route would work, but there are other lovely
gardens in the area. I've totally blocked on the names of the two
gardens in Swansea, for example.

The route would work, in the order you have stated.

--
Howard Neil