>I would like to >hold the camera at about knee level without looking through >the viewfinder and without live view.
I have to ask: why not LiveView? I find that LiveView at a distance and severe angle is sometimes still good enough to show me an outline of my subject. I only see a rough outline at this angle but it confirms I'm on subject.
>If possible I would like to blur the background
That makes it difficult as a blurred background means shallow DOF which then means accurate focus is needed. Otherwise, you could do like "street shooters" do. They set their camera to something like f16 and manual focus to something like 15 or 20 feet.