How can I save a file to a specific "keyed" location?
You can use Command -> Shift -> G in the save dialogue box too, just like in Finder.

Default Folder X is great for saving some as favorites or specific defaults for certain apps. IT does way more than just keyboard shortcuts, but that is one of its super-powers. 


https://www.apple.com/accessibility/mac/mobility/


Accessibility lets you use keyboard commands to select graphical elements and then tab / type / navigate to whatever folders you prefer. 



Control F7 allows tab to select more items and move around using your keyboard in the save dialog.