hi there! I’m not at all acquainted with role-playing games. But I’ll make the following observation. My brain would have a hard time mixing campaigns up at the same level as other aspects of game play. I would want to do this, inside an Category 41 RPGs:
41.00 RPG Management and Meta
[41.01-09 -- standard zeros]
41.10 Campaigns
2025-07-01 Game XYZ -- Campaign 'Dark Forest Trails'
2025-10-20 Game ABC -- Campaign 'Goldmines of Gologon'
...
41.11 Game Notes and Ideas
41.12 Character development
...
It’s perfectly OK make subfolders for campgains, because they have a predictable name, and presumably they all have a similar internal structure for which you could make a template at 41.02 Templates for RPGs (see here for the standard zeros).
My brain can now relax because everything which is at the same level seems to me to have the same level of abstraction/concreteness. As an aside, I wil note that in my system, I actually have a completely flat single folder and I type-to-filter a particular topic – but the tags which I use to identify topics and subtopics still map strictly to a carefully thought out hierarchy. In your case, I assume you want to stick to normal JD practise and have a two-level hierarchy.
Now, this presumes that Area 40-49 would be dedicated to Hobbies. If you map out everything in your life, and determine that you can easily dedicate a whole Area to RPGs, then this can all move up one level:
40-49 RPGs
40 RPG Management and Meta
41 Campaigns
41.02 Template for Campaigns
41.10 2025-07-01 Game XYZ -- Campaign 'Dark Forest Trails'
41.11 2025-10-20 Game ABC -- Campaign 'Goldmines of Gologon'
....
42 Game Notes and Ideas
....
This saves you one level of folder navigation, but whether it is feasible depends on whether you can afford an Area for RPGs alone. Based on your other information, I’m guessing you easily could. You could then use 41.01 etc for the ID, or some other identifier like the date, game name, and campaign name – following the rule that if things naturally have an ID already, use that.