OK, I got it wrong.
GUADEC did not really end on Sunday.
On Monday, I went to my first hackfest - the PyGObject hackfest. It was fantastic. Thank you to Martin Pitt and Paolo Borelli and John Palmieri and everyone (sorry, I am terrible at remembering names!) that helped me to learn so many new things. Thank you, in particular, for your patience with this beginner.
On Tuesday, I finally sat down at a table with Tiffany and we redesigned what I am doing for this summer, given the many useful suggestions we had during GUADEC. The new idea: you should be able to consult the "example" pages (which are divided into: example, code for the example, useful methods, API references, exercises) both from a page that groups the widgets by "category" (windows, display widgets, buttons...) and from a page that gives you a series of "lessons" - a more "sequential" tutorial. The former is aimed at more expert hackers, whereas the latter is for almost absolute beginners. In the latter there are also the "theory" pages (properties, the MVC design...). For the order of the tutorial I owe a lot to Taryn Fox's page here (although I changed some things).
Any suggestion is, as always, very welcome!