Where are some places, and is there a place in Diamond?

You can store items in any settlment you own are allied to(by using containers inthere or placing your own), in daimond city you can get an appartment.

I've got a long and low cabinet (my brain fails to get the proper english word for it, a dresser maybe?).

I store all my apparel in it, that has modifiers.

Now each time I come back there, dogmeat barks and tells me "I found something".

Like a good boy with no long term memory (just like it's owner hahaha).