I'd revolve the story around Elaine. Dominic Armato once said that Elaine's always had Guybrush's love by default, and that he'd like to see her earn it. I love Elaine - she kicks substantial amounts of ass, especially in TMI04+05 - but the next story should try and explore her a little, maybe even shed a bit of light on her actions in TMI.
I get the feeling DeCava is going to return. Good! That guy has so much potential. He probably writes himself.
Hmm...my ideas, though. Well, I'd start the story by having Guybrush lead an assault against LeChuck or the Voodoo Lady, maybe a little timidly. There's this part of me that thinks it should be about him attempting to retrieve the dead back to the land of the living, but it's a little too Shadow of the Colossus. Maybe atone for something? He's screwed over loads of people...but then again, that's the point of the trial.
It'd have to be something NOT involved with finding a McGuffin, that's the thing. I should go read a few pirate biographies first, and then get back to this topic.
the image that comes to my mind is LeChuck attempting to get married to someone in a teal green-lit room with floating candles, though that person is not Elaine. Guybrush is attempting to stop it. I don't know why.
See, now you've got me stretching those writer's muscles. Gah. I'm trying to write my own short stories, damn you. I'll see if I knock-up an outline or something, and then stick it on here in the next few days.