Is it possible to move the camera, after rendering the scene, through keyboard input as you would move a character in a video game? In writing the title, I was given a "Questions that may already have your answer" link that was ALMOST exactly what I was looking for. However, on that page neither the question nor the answers specified what I want.

I am working on a school project, and I have been using cycles materials as I was unaware they could not be used in a game. I am wondering, is it possible, in a cycles render, to have the camera move through the scene through WASD input? If not is there a way that I could convert the cycles materials (I think they're nodes, and that's why they can't be used in the game engine right?)  to materials usable in the game engine besides baking? I tried that and it didn't work.

I am relatively new to using Blender, as this question probably indicates, but I should be able to work with whatever advice I am given. I also apologize for the multiple questions in one.
I think the answer to your question is "no". You can't "walk" into a render, whatever method (or program) you use to render. A "render" is a non-interactive image (or a sequence of for an animation render), so the best you can do with an image is zoom, pan, but you can't do what you asked.

What you wish to do (ie: walking into the scene with some WASD keys setup) needs an interactive scene, aka a "game". Blender "game engine" allows to create interactives scenes but, as you discovered, this "game engine" uses "blender internal" material types.

The "game engine" is there since many years, well before cycles renderer came, and it is also understandable that it uses "blender internal" materials, because of course cycles gives  way better results, but is also usually way slower than the "blender internal" way of rendering scenes.

You could, perhaps, try this: you could try to "bake" cycles materials to textures, UV map those textures to your "blender internal" objects, and then use the game engine to "walk" inside a scene that appears much like if it was rendered with cycles... it's a sort of precalculation. It will not be like a realtime cycles game, but it could also allow for much better results than the standard "game engine" ones.

I remember a cool project, let me search...
Found! Look at this: http://www.blendernation.com/2014/07/23/the-horror-of-cycles-baking/ this has been done with this method, I think. Also you could learn something about this setup watching this: https://www.youtube.com/watch?v=sB09T--_ZvU

HTH