NOTE: To get this to work the rift MUST be in extended mode & the LED on the front of the unit must be blue. If it is yellow this will not work. If yellow play with switching direct/extended mode in the Rift software & toggling power button on the Rift
To get DF & DK2 working using extended mode on my dual screen setup I did the following:
Exit DisplayFusion
Power up Rift to blue LED - open display driver software, in my case AMD catalyst, driver config window will appear on the Rift.
Look into Rift, locate the Catalyst/Nvidia window & drag it out to a standard monitor using mouse. (Get used to this process when running in extended mode).
Setup monitors like first 2 screens here:
http://imgur.com/a/ifK0V#0
Your standard monitors should display native resolutions. I have my second monitor on the left, but I guess the reverse applies if yours is on the right. NOTE Rift orientation HAS to be set to portrait to render correctly (side effect of using a mobile screen). The Rift should be the primary monitor.
Apply settings & close window
Launch DF & set its monitor profile as in screenshot 3 ie replicating the settings you just setup in display drivers.
In my experience if you try to use DF to change catalyst settings it will ALWAYS error when the Rift is plugged in.
Now, when you power up/down the Rift with the software in extended mode, the resolutions/number of screens should switch correctly.
ProTip: You can also setup a wallpaper profile to show a black wallpaper on the Rift to lessen the chance of screen burn, & a white one for cleaning the screen of debris.
Also when starting Unity based games, highlight the extended mode .exe, hold shift & double click the exe, this will open a basic config, make sure res is set to 1080, the monitor is the rift, & windowed mode is not selected. The new settings for that app should persist.
It's a pain but personally I think it's worth getting running as direct-to-rift has some issues with FPS & judder right now.
HTH