ending-campaignsgm-techniques
I am planning the next campaign while the current one comes to a close. Our group favours sandbox play and I facilitate that with Icar's event driven system. While writing down the list of events needed to fill the campaign with interesting plot hooks and set pieces, I was wondering if it is wise to plan a big finale.
I want to avoid fizzling out and at the same time I don't want to railroad the players – they won't like it. Should I have an inkling of the end before we start?
The essence of sandbox play is following where the players lead, and it sounds like you're already doing that.
What adding randomness does is make the world feel more alive and larger than the thread that the PCs are pursuing/creating, allowing the players to make informed decisions about where they want to drive the game. You don't need to be constantly interrupting them with random encounters, but using them as a "spice" enhances the game and increases the players' knowledge of their environment, which itself increases the players' agency.
And don't worry about diversions derailing the campaign or slowing its advancement—the point of a sandbox is that there is no right path. If your players choose to diverge from their goals… it's because they have more goals than the one. If they want to advance one goal (not "the campaign"), then they will prioritise that goal even when distractions occur.
As long as your randomly-added distractions aren't mini side-railroads that force the players onto them, you can trust that they won't interfere with the players' freedom to choose their direction and speed. If the players choose to be distracted: that is where the campaign is. If they choose to not be distracted: that is where the campaign is.
Just remember that the campaign is where the players lead, no matter whether it was their idea or yours, and you can cut through this Gordian knot of worry about whether you "should" distract them with random things and whether the campaign is advancing at the "right" speed. There is no right speed or direction in a sandbox, only choices and outcomes.
To add to fgysin's answer, if your campaign takes place over longer scales, with travel taking e.g. weeks, quad paper becomes useful:
In this case you'd use either a separate sheet, the other side of the paper or the right half for notes. Cross over days that go past with nothing significant happening, but use a number for notes if something is important:
Depending on the size of the paper and grid, you can fit a year on 2-4 pages, meaning even decades-long campaigns stay (relatively) organized.
Regarding who maintains it, as GM you can more easily set yourself reminders in the future or notes about NPCs if you do it. However, if a player does, you can still ask them to mark down e.g. a star without telling what it means. Sneaky way to hint at a deadline...
Best Answer
You can have an ending in mind, but remember that even writers are advised:
And we GMs are not even solo writers, though we share many of the same skills. As soon as making that ending happen and the actual game that's being played with your fellow players part ways, kill your darling ending with fire.
An ending that organically follows from the events of play will be infinitely more satisfying for everyone else than the ending that you had in mind. As the original writing advice explains (paraphrasing), "A bit of writing that you love is probably worse than you think because you can't be objective about it." Kill your ending as soon as it no longer serves a purpose and threatens to become a millstone around you and your players' necks.
What is a pre-written ending's purpose in a sandboxy game, then? It's something to aim for, direct your imagination, and breed hooks that make the beginning go well. It's a framework around which you can build an initial situation that will drive your end of the game, just as their character concepts drive the players' end of the game yet are subject to change and development. Once the game is off the ground and humming along, a pre-planned ending's purpose rapidly diminishes. It has given birth to its plot-hook children, and must gracefully step out of the way so that its children can inherit the game and pursue their own destinies, without parental meddling from the pre-planned ending.
Having an ending is, ironically, only really useful (in the sort of game you're talking about) for creating beginnings, and is a terrible way to create an actual played ending. For ways to create a good ending before a game fizzles out, you actually want to think more about putting a time limit on the campaign itself to focus it and give yourself a deadline for pacing purposes, and the players a deadline for accomplishing their goals. A campaign with an indefinite timeline almost always fizzles out rather than concludes, but a timeline with an ending that everyone is apprised of sharpens everyone's attention on giving stories a proper arc and bringing loose ends to a more-or-less tidy conclusion.