I'll avoid bumping this thread for a while while I gather research materials.
Interactive map of MIT buildings:
Map of the main campus with the tunnel system highlighted in red:
https://web.mit.edu/facilities/maps/mit_Tunnel_map.pdf
Blog post about hanging out in the tunnels:
https://mitadmissions.org/blogs/entry/underground/
I'll base some details on real locations, but I've never actually been inside any of these buildings and I don't want to bother traveling to Massachusetts any time soon. Most of the action will take place in an imaginary "magic tower" or "ivory tower" that supposedly gets built in the future. It could either replace the Strata Center (and be a parody of that building) or one of the other buildings that looks like something normal instead of a nightmare. I haven't decided yet.
Synopsis of prologue:
The player is a freshman, on his way back to campus for the first day of class after partying at some other school (like Northeastern). He boards a red line train and bumps into Alyssa for the first time. They get off at the same stop, not realizing they're classmates, and have an awkward walk to the lecture hall together. Substitute instructor Yomi (the SICP snake) begins class and assigns whatever homework. (Their "real" teacher is mysteriously absent throughout the story.) After class is dismissed, Alyssa rushes to talk with the player. Eva intrudes on their conversation to size him up. Her first lines are some sort of thinly veiled threat.
After that, they'll have several more classes together where the player gets the chance to become closer to different characters (Alyssa, Eva, Ben... maybe others) before the routes fully diverge.
The actual curriculum is very malleable, and in different years they skip some parts and focus on others. I'm considering incorporating that into the story and using different material for different routes, but I haven't decided how much actual SICP content to intersperse with the drama. I'll start out leaving all of it as placeholders while I work on the story. It can be rewritten into real excerpts/exercises during later revisions.
I will include some Touhou references, and imply that the Touhou characters are real and working or studying at MIT, but they won't be a major presence because that would be too much of a distraction from working on the core content.
Some of the characters are very well-formed in my mind. Eva is the best-developed right now. I can get a lot of mileage out of her special combination of confidence and social awkwardness. For example, during Alyssa's route, she will appear out of nowhere to tidy up Alyssa's clothing. When informed that she's interrupting a date, she will tell the player, "You can leave now."
Ben is the least well-developed. I need to read more SICP.