I can't remember if I might have seen this document linked on John Fiore 's blog before, but Steve Lopez (at https://fourcolorglasses.wordpress.com/2011/05/23/a-decent-primer-on-solo-rpging/#more-897) described it as a "decent primer on solo RPGing". It is focused on D&D 3.0 and up, apparently. Enjoy!
http://shiftkitty.angelfire.com/DDSolitaire.pdf