Yeah, Story of the Blanks was certainly a big inspiration for this, but I don't think the 8 bit style matches the atmosphere here as much as it did there ... I'm thinking more of a sketchy or sort of watercolory style for At The Mountains. It'll also be a bit longer than Story of the Blanks, and there's cutscenes and things too, multiple endings ... so more content in general. But the gameplay is fairly similar, not much more than walking around and looking at things.
But yeah, thank you for offering your help ^^ For sprites we'll eventually need all the mane six and that's about it, and I don't know whether you were thinking about doing floor maps too ... or if you'd like to do the cutscenes that would be very nice as well ... I don't know, you should email me, then I'll send you the design doc I scratched up, and I guess we'll go from there.
In the meantime, maybe if you feel like it you can do a title screen? I don't actually know what the title should be, I haven't been able to think of a good one, but it would be cool to have a nice splash screen for it to go on. Maybe something with Twilight and Applejack gazing off at the distant mountains or something. I don't know, you're the artist, I don't want to dictate what you should draw lol