Campaign meta-game [closed]

I’ve been looking for a campaign meta-game for my players to track elements during adventure ‘downtime’ and was curious what people in the community have tried?

For example, an island world campaign (a-la fantasy Firefly/Cowboy Bebop) where players have to worry about maintaining a ship to travel between adventures.

They would have to maintain cargo, ship repairs, and relations between islands that affect events during game time.

I’m stuck trying to make some mechanics that would be impactful to a group of players however, any ideas?