I had honestly considered writing my website in common lisp, but discarded that idea because I couldn't find good documentation for the RESTAS web framework.
Do you mean the official documentation, or 3rd party examples and tutorials? Andrey has been working hard at translating the official docs to English the past few months: http://restas.lisper.ru/en/
As for tutorials, you are right that there could be more. Between https://github.com/archimag/rulisp and https://github.com/archimag/cliki2 there are some good example sites built in RESTAS.