@Katofhyrule12 A Historical Library is a great idea. I do agree that books are getting fewer and fewer these days. Though from what I've seen, books seem to be quite popular with young adults like myself, at least where I live. I'll probably add a library in Willow Creek, where I'm planning a more historical town. I like the idea of having restrictions on technology.
As for history, my idea is that this save in set not only in the future, but in space. Each world, being its own planet, would have its own history. Humans have developed ways of warp speed travel and have colonised other planets. Most of the planets will probably be sort of a mix of aliens and humans, since I can't really control what kind of townies generate. (though I do plan on controlling their clothes through a mod) There will definitely be varying income levels. I intend to use Evergreen Harbour and the starter neighborhood in Del Sol Valley for the lower class sims, who tend to use older, more cyberpunk style technology.
A living museum is another great idea! There is one near where I live that I've visited before. I hadn't thought about holidays, but in addition to the normal holidays, like Christmas and Thanksgiving, I could also add some alien holidays as well. Visiting a living museum on holidays is a good idea too. You could even add an "Earth History Day" holiday.
I hardly use the off the grid trait, and I usually don't use story progression since I play with aging off most of the time, but I think that would be interesting to try.