In a standard Open/Save dialog, you can type Command-Shift-G, pause, and then Insert Text by Typing a full path, including file name, and then %Return% and that will select a specific directory and file.
In a standard Open/Save dialog, you can type Command-Shift-G, pause, and then Insert Text by Typing a full path, including file name, and then %Return% and that will select a specific directory and file.