Hi,
Currently there is no way to set the location or frequency of the auto-save.
The project file is located in C:/Users/<username>/AppData/Roaming/NCH Software/VideoPad and is "autosave.vpj". If you can't see the AppData folder, it's hidden by default as it's considered a system folder. Since this is in the AppData folder, be careful not to delete anything you're unsure whether you can safely delete. A lot of programs may not run properly if you delete a file they need, and may require a re-install. The autosave.vpj file however, is safe to delete as long as VideoPad isn't running.
The frequency of the autosave is 2 seconds after the last change made (a new change made in this time will push back the time to 2 seconds from new change).
The autosave is also deleted when VideoPad closes normally.