This might not be the best solution, but at least the first solution that struck my mind. Although I didn’t get it to work exactly how it first was intended. (freezes playback during drag)
If you don’t like the result maybe it at least can work as a push in one possible direction.
You would also probably want to constrain a camera aim to something to make it a bit more interesting than just translations.
Anyways, run the script and it will let you drag/click during playback a new keyed position for the selected camera.
Remove last line if you want to start playback manually.