Fascinating thread.
As a side question: was Sept 1970 the high point of RM circulation? I think my first " bought new" copy was then too!
I personally find two sorts of layouts inspiring: those that have a very believable "backstory", so that they seem to serve real communities; and, those that can be, and are, operated like a real railway, with at least a bit of complexity to the traffic pattern.
The seriously brilliant ones fit both descriptions, The Buckingham Branches, The Madder Valley etc.
The Buckingham Branches is so good a concept that I'm forever looking out for remains of the routes when I drive across the area ....... Leighton Buzzard (Linslade) seems more real than certain real stations!
Lately, I've got into "prehistoric" model railways, working my way through model railway magazines and books from 1909-1911, 1925, and 1938 as sample years. There is a lot to learn from our ancestors, especially when it comes to designing for operation, rather than appearance, so I've found even the most ancient things quite inspirational.
It's quite interesting to read things that were written when "modern image" meant the LNWR's latest express engine, so I will add the leading name from that era: Henry Greenly. He and WJB-L effectively invented our hobby!
Kevin