I think there are a lot of ways you could take it! If you wanted to expand it for multiple people then adding rules for player interaction and how the party takes care everyone as everything falls apart and if you want it to remain solo then I think adding more depth for how you interact with the npcs in your camp and how they interact with each other. For example adding events where they request things of you and depending on how you respond, changes how favorably they think of you and if favorability gets too low something bad happens etc etc.