Ooooh my god one of my favorite novels is The Book of the New Sun so this is RIGHT up my alley. Do you know what system you’re going to be using?

People get the idea of a West Marches game all mixed up. It’s all about reducing the level of obligation. Rather than you scheduling and preparing games, you expect your pool of players to do that for you. Rather than needing a specific “party” of player characters to keep showing up, the “always return to base” requirement means people can drop in and out as it suits them. Someone from the last game can tell everyone what happened, what they found, etc, and if someone’s interested in something, they can put a party together and go “hey GM can you do a game on [whatever day]? We want to try X”. It’s not for everyone but with the right (and large enough) group it’s a pretty low-stress way of doing things.