where are the Castle, Dunwich Borers and Trinity Tower? I just want rough advice where they are, please

the castle is in the SE portion of the map, on a protruding coastline.....but you will want to be well equipped.

The Castle is along the west coast of South Boston, on the little sort of peninsula that has a lake inside of it - you eventually go there for a Minuteman quest if you didn't know already. Dunwich Borers is in the northeastern part of the map, further inland and not along the coast. Trinity Tower is in downtown Boston, I think it's the second tallest skyscraqer in the city skyline. Once you're close you'll get a radio signal that'll point you to it though.

thanks both, I'm not doing any MM quests in my 1st playthrough, waiting to do those and Institute in my 2nd to make it very different