Book Road Trip
My go to answers for these kinds of things are Ireland and Italy but I will try to avoid using those two this time around!
Alaska: The Alaskan Courage series by Dani Pettrey
Washington D.C: The King by Steven James
Spartanburg and Columbia, SC: The Women of Justice and Deadly Reunions series by Lynette Eason
New York City: A Most Peculiar Circumstance by Jen Turano