Normaly you should be able to drag and drop everything across the two monitors except 3D accelerated windows because they are bound to the surface they are initialized, maybe it will go down to some lousy fps or crash.
You have to start lfs on the root monitor - I haven't figured out if there's a way to say it should start on monitor 2 like I can do in Linux Windowmanagers.
Hope this helps
cheers,
Sven