Man, if only I had some kind of access to these way back when, they would have served me very, very well when I first constructing my model:
Architectural style guide for Sesame Street distributed in 2000.
muppet.fandom.com
Architectural style guide for Sesame Street distributed in 2000.
muppet.fandom.com
Architectural style guide for Sesame Street distributed in 2000.
muppet.fandom.com
At least one old issue of SS Magazine I had featured a fold-out poster with this illustration of 123 that you could color that I used for reference for my 123 model, but pretty much everything else in the model was more or less free-hand, so-to-speak.