Question about "live" UV-mapping

Is there a way where I can UV-map my box on the right with one or more camera views of the 3D model on the left? What I mean is - can I use a camera view as source for a specific UV-unwrapped side of a box?

I am making a paper model of a castle, and I am quite frankly irritated by having to render 5 views (sides and top) and then use that to UV-map the box, whereupon I must export as a paper model.

There are quite a few individual parts to the castle.