You should find them in highway rest areas and mall food courts where there is a Nathans; the Arthur Treachers are part of the Nathan’s now. The nearest one to me is the Willowbrook Mall in Wayne NJ.
They aren’t stand-alone restaurants (even within the mall/rest stop), and the sign will only say “Nathan’s”. The lighted menu above the register dedicated one part to Arthur Treachers (hush puppies, fish & chips, cole slaw), the background of that section of the menu is the Union Jack.
Thanks. None down my way I think. Will have to do a search.