This add-on is really simple so I'll keep this simple as well.

Interactive Orientation

As you can see in QuickView's interactive orientation you will be brought to the respective orientation when you move your mouse above the set threshold (can be changed, see below).

When you're below this threshold you will be sent back to the default viewing orientation you set in the settings. 

Pressing 'P' while in this mode will allow you to toggle perspective (shown as a "(P)" or "(O)" after the orientation name).  

After you've reached your desired orientation, press either LMB/RMB/Esc to close out.

You can move around your view as usual while in this mode (panning, zooming, etc).

Settings

In the settings you can change the threshold for when the viewport will change to the desired orientation.

You can also change what the default orientation will be (the orientation used when below the threshold)

Also change the keybinds if you have any other add-ons conflicting with the standard ones.

Auto Perspective: Disabling this will let you keep the current projection (moving the view will not auto enable perspective) while in I.O 

Return to Perspective: When using Orthographic for default projection, enabling this will enable perspective view after you are finished using I.O.