This is like barn-v7, but I'm attempting to use CSS to set the size of the canvas, and to use the determined size of the canvas to set the size of the renderer and the aspect ratio of the camera. This idea is due to http://greggman.com/downloads/examples/three-by-css/three-by-css-no-resize.js

Also, this shows setting the initial camera location and lookAt using the geometry and bounding box of an object in the scene. However, (1) mesh objects can be different from their underlying geometry if they are transformed, and (2) it's still fairly cumbersome.