One of the things I've noticed is that Ginger Island is not particularly well integrated with the rest of NPC scheduling and dialogue. Pierre can tell you that he'd rather be outside than running his shop one minute, and the next you'll find him enjoying the Resort. Or Jodi would tell you to wipe your feet off when she was outside on the beach. For that, this mod implements specific dialogue keys that are only used while an NPC is (a) on the mainland and (b) headed to and away from Ginger Island. I was going to write dialogue lines for everyone but honestly I couldn't come up with lines for...a lot of characters, actually. So a few have lines, but for the rest, I hope the included content pack and documentation are clear enough.

Additionally, NPCs would just head directly to bed after going to Ginger Island (with the exception of Gus), skipping their usual evening schedule points, leaving, say, Demetrius dancing alone if Robin went to Ginger Island. GIRemainder schedules now take over for the evening instead, so characters might make a stop or two before going home. These are included in the optional CP pack. Instructions to adding more can be found here.

The original point of this mod was to change those two things. A little scope creep may have happened. This mod has an option to completely replace the usual Ginger Island scheduling to handle the following:

Custom NPC groups. One of the more charming things I found about Ginger Island is that the NPCs actually attend in groups. For this mod, the vanilla groups have been moved to a data file, and mod authors can easily add more visiting groups. (Details in the documentation - just know that no additional groups for custom NPCs are included in this mod. I believe RSV and Jorts and Jean use this, though! Both highly recommended!)
More NPCs visit Ginger Island. If you, like me, enjoy having large numbers of NPCs, it's sometimes hard to catch a specific NPC going to the resort. This mod will let you increase the cap to up to 12 per day by setting the configuration option Capacity. Great for running around gifting people!
NPCs can wander onto IslandSouthEast and IslandNorth. Most won't get too far, but some might be a little more...adventurous.
Gus has a dedicated day. Set the config options GusDay and GusChance, and he'll have specific days where he's more likely to go to Ginger Island...
Willy, Sandy, George, and Evelyn can go to Ginger Island. (Configurable). Sandy and Willy will even leave a box on their counters so you can still shop! My friend Elizabeth has made her these excellent beach sprites, available here!

Install

Install the latest version of SMAPI.
Download and install AtraCore.
Download this mod and unzip it into Stardew Valley/Mods.
Run the game using SMAPI.
Optionally: download the small example content pack, which has GIRemainder schedules and a few dialogue keys, mostly just replacing lines I felt were most egregious.

Uninstall

Simply delete this mod from your mods directory.

How to use
Configuration settings:

Note: you will need to run the mod at least once to generate the config.json file. Generic Mod Config Menu integration is supported if you want to edit the values from inside the game.

EnforceGITiming will output warnings if schedule points are placed too closely to each other and skip that schedule point, but only if UseThisScheduler is false. Recommended while setting up/debugging schedules.
UseThisScheduler will cause the mod to generate Ginger Island schedules. The remaining settings will only have affect if this is enabled.
Capacity sets the maximum number of visitors to the Ginger Island Resort. Will allow values up to twelve.
GroupChance sets the probability a group of NPCs will be picked to visit the Resort.
ExplorerChance sets the probability a smaller group of NPCs will explore Island North.
GusDay and GusChance set a day that Gus is more likely to go to the Resort, and the chance that he'll be there. (set GusDay to None to disable this feature.)
AllowWilly allows Willy access to the Resort.
AllowSandy allows Sandy access to the Resort. (Psst! If you want her to have beach sprites, check out violetlizabet's mod here!)
AllowGeorgeAndEvelyn allows George and Evelyn access to the resort.
AllowWizard allows the Wizard access to the resort.

Additionally:

Three console commands: av.gima.get_schedule shows you their schedule of the day.av.gima.get_islanders tells you who is going to the island. Do note that if UseThisScheduler is set to false, GIRemainder schedules are added one per ten minutes starting from 610, and thus they may not be in until 7AM or so.

av.gima.get_locations_list dumps out the current value for NPC.routesFromLocationToLocation.

For more documentation, see the author guide.

Compatibility

Works with Stardew Valley 1.5.6 on Linux/macOS/Windows.
Works in single player, multiplayer, and split-screen mode.

Compatibility with other mods: mostly unknown. It should be relatively independent and thus compatible, and Island schedules are actually perfectly normal schedules in the code, they're just generated randomly by the code. Let me know if there's specific incompatibilities, but do keep in mind that I'll only build in compat for mods that are open source and only when I have the time and energy to do it.

If you have a mod that changes the Ginger Island maps, this mod may be incompatible, since both it (and the vanilla game) hardcode locations for NPCs to stand on. I might do something about that in the future, but it's not on the top of my list.

Current compatibility list:

No known incompatibilities!

Additionally...

Translations would be very welcome! DM me or send me a pull request!

Requires SMAPI, uses Harmony.

All donation points for this mod go to Doctors Without Borders. Please consider supporting them if you like this mod!
Looking for something else? Please consider my other mods!

Ginger Island Mainland Adjustments