The suggestion from SonyDennis in that ancient 2003 thread was Ctrl+Down Arrow. For me it makes the entire project (length) display on the timeline. No mouse involved in this shortcut.)
(Before jetdv's comment there he already had more than 800 comments on the SCS forum. Up to more than 7.5K by now.)
I searched for an hour last night, but couldn't find Ctrl+down arrow, which is very OK for me as I want to assign it to a button on my Shuttle Pro V2. So far I have always used the mouse wheel - but to get an overview of the project again, Ctrl+down arrow is ideal.