...what would they include in it?

What kind of resources, maps, tools? If many pairs of sunset and twilight were to stay there for a prolonged period of time what kind of residential areas/buildings would they make?

Some ideas to start:
-a giant library full of knowledge from many different dimensions for sci-twis and princess twilights alike

-a garage with tech from steampunk, magitech, scifi etc. universes for Sunset to work on her motorcycle (which she totally has!)

-Cafeterias full of Twilight's favorite hayfries and also a quesadilla stand that a Sunset uses purely to prank her twilight ;)

-recreations of the Tree-library for nostalgic, homesick princess twilights to stay in!

-A Starlight Glimmer daycare to take care of Twilight's troublemaking apprentice while Twilight is busy having multiverse adventures! (Complete with people in Trixie or Sunburst costumes to read her the Communist Manifesto)

Please come up with more ideas and post them here! What would these two hyper-prepared women of science and magic leave for their alternate version selves?

6251985
Utterly unhackable retina, gene, and magic-signature locks guarding blackmail material and other hilariously embarrassing moments from across the multiverse. (Funnily enough, the Twilights and Sunsets installed their respective vaults right next to one another. None of them has yet realized this.)

Lizard, owl, and dog sanctuaries for times when pets want to visit or need to be evacuated from imperiled timelines. (Possibly near the Starlight stable, depending on how much they're trusted.)

Morphic field manipulators, for those times when you'd rather be a different species.

Anti-Pinkie defense systems to block party entity incursions. (Current version number: 43.6. Success rate: Still 0%.)

6251985
* A catalogue of all alternate dimensions and the current status of their Twilight and Sunset
* ID tags
* A note of any other dimension-hopping beings they've encountered that may be hostile to them
* A special magic flame that can send letters to any Spike in the multiverse

-A mechanical princess Celestia whose only purpose is to give terrible advice.
-A helpdesk to direct people to the timelines they want to visit. This may be manned by different Sunsets and/or Twilights and spending a week working there is considered a sort newbie initiation ritual so they can get the hang of where everything is.
-A 4d chess board; because several Sunsets and Twilights grew bored of the simplicity of 3d chess.

A hotel for other travelers other than Sunset or Twilight. They aren’t the only ones hopping the Verses!

Large Garden, with many flowers.

Massive Biodome around center area. (With changeable weather )