Interactive 3D view with simple UI

I know what I want to achieve but am stuck on implementation.
I need to replicate what I see in Geometry view with an interactive 3D view, and also add a simple UI with a few buttons. In Perform mode.

There is the Camera Viewport component which I have been playing with this afternoon but still unclear on how to get what I am after. Could anyone possibly provide a hint or direction(s) I should take?