I have a group of friends who enjoy playing TTRPGs together (primarily D&D 5e) but who do not live near each other. We are looking for ways to play together more often, but some of the group members can't or prefer not to play online campaigns, so we are limited to playing in person a handful of times per year. We love playing one-shot campaigns but would like to have something that lets us flesh out characters and stories more, even if the timescale is long.
An idea we discussed was running a campaign in which the characters themselves had some reason to gather together once per (game) year but were otherwise doing things on their own the rest of the time, probably using a different/extended ruleset. An example of something like what we're imagining, in case my description here isn't clear, is included at the end of the question.
I'm looking for asynchronous rule-sets/extensions or 5e game extensions that could be dropped in or used with infrequent in-person D&D 5e sessions to enable this kind of play. I would welcome good subjective response about what did or didn't work with such rules also.
Example Gameplay Concept
This is a very basic example of how we would like to run a game; it was quickly invented and is not meant to hold up to scrutiny, just to portray the game concept w.r.t. how in-person vs. asynchronous play would work. I'm interested in rules that could accommodate these levels of asynchronous/in-person play with D&D 5e (or something very similar) even if the kind of game we would play asynchronously is much different.
- Each PC begins the campaign as a low-ranking member in a particular guild/political organization/faction;
- The campaign starts with an in-person session in which all the PCs have some reason to have traveled to [capital city] where they are inducted into [secret society] that is trying to save the world from [BBEG]; the PCs are a "class" in this secret society and they are tasked with preparing their respective guilds for [coming conflict].
- After this session, the players and the PCs all travel home to their respective locales, but the game continues asynchronously over email/phone/discord. The PCs are managing resources, making decisions, writing letters to local authorities. This might be more like a strategy/resource-management game or a game of politics, and it would have to be flexible in that I wouldn't want to punish a player who only had time for a few minutes of this kind of play per week, but I would also want to be able to reward a player who really got creative with this kind of play. I'm not looking for any specific mechanical requirements here aside from that players be able to engage with this part of the game at their own pace asynchronously.
- This section of the campaign might also include occasional 1-on-1 sessions or small-group sessions, as the story-line and player availability allow.
- Six (real-life) months later when all of the players are again gathering in the same physical place, one (in-game) year has passed and the PCs are again in [capital city] for [important event] at which [BBEG] has something sinister planned. The PCs must leverage their guild resources as well as their personal abilities in order to foil [BBEG]'s plans. This likely plays out over something like a long one-shot session.
- After the session, everyone again travels home, and the asynchronous portion restarts, though it will of course have been changed by the events of the session.
- Repeat until the campaign concludes.