Is there a way to make a quick animation PREVIEW, to evaluate motion, etc.? I want to evaluate motion, camera moves, etc., preferably in OGL -- I can't seem to find this in the Manual, and it seems no one has covered it on YouTube (at least I haven't found it if it's there) ... There must be a way to make a quick PREVIEW of the animation that can be viewed in real time, without waiting for the entire render ... If so, HOW?
You can OpenGL render a movie with the 'Render OpenGL' movie button, found in the lower right header of the viewport.

It'll use your regular render settings for frame ranges/formats.  Personally, I like to render a sequence of pngs/jpgs into a temp directory, and then load the sequence in the Sequence editor.  But some people prefer a separate movie player application.