Is there a 'fast way' to print all the Plone training docs (for example by generating a pdf from all the docs)?
You can download a html-zip from https://readthedocs.org/projects/plone-training/downloads.
Using http://www.sphinx-doc.org/en/stable/builders.html#sphinx.builders.latex.LaTeXBuilder and adapting the conf.py from the training-docs repo you could also create a pdf version.
The easiest way to use it when you are offline is to clone the repo and build it locally:
It is nice to have it on paper, at least if summer returns