Since last update, I have added more set dressing in the first section of the space station, including a landing bay full of Myasishev-48s. The temptation to wrap up the game by having the player make a terrifying re-entry in one of them is almost irresistible, just so you know.
I also started on the next section of the game, a monorail trip across the center of the space habitat. I made the monorail car a vehicle, which is rather trivial in Inform:
The monorail car is in West Lobby. The monorail car is a vehicle.
Now if you "enter car" and then start typing directions, you can drive around in it. Restricting the monorail car to only being able to drive along its track isn't much more complicated:
Monorail Track is a region. West Lobby, Habitation Cylinder West End, Habitation Cylinder West, and Habitation Cylinder Center are in Monorail Track.
Instead of going by monorail to somewhere not in Monorail Track, say "The monorail track doesn't go that way."
And that's pretty much that, of course, except for coding up the inevitable plot-oriented disaster that hits in the middle of your trip. That being said, as I thought about vehicles more it became hard to avoid casting the whole example in a more seductive fashion...
"They All Laughed"
Battledroid Garage is a room. "Ah yes, the heart of your sinister technological lair, disguised as an anonymous warehouse in the middle of the city. A giant garage door to the north leads out to street level."
Battledroid XM-60 is a vehicle. "The heavily armed, twenty-five-foot-tall Battledroid XM-60 towers over its surroundings nearby."
Philadelphia is a region. Germantown, Chestnut Hill, Juniata Park, Kensington, University City, and Rittenhouse Square are in Philadelphia. Chestnut Hill is west of Germantown. Juniata Park is east of Germantown. Kensington is south of Juniata Park. University City is south of Germantown. Rittenhouse Square is east of University City. Juniata Park is north of Battledroid Garage.
Instead of going to Philadelphia when the player is not in Battledroid XM-60, say "That would be missing the whole point of your revenge."
After entering Battledroid XM-60 for the first time, say "Bwa ha ha ha ha! They called you mad at the Academy! Well, you'll show them who's mad! You'll show them ALL..."