1) A very common instinct, for novice IF authors, is 'I want to map my house/apartment/neighbourhood/dorm room/campus.' This approach isn't inherently awful, but because so many inexperienced authors try it, they have a pretty bad reputation as bland and boring. (We call 'em My Apartment games.) Not trying to discourage you, just giving fair warning. It's great as a learning project -- but it's possible that you may want to think carefully about publishing the first IF game you ever write. (I'm deeply grateful that I never did.) But there's been some discussion in recent years about the potential for nonfiction IF, including autobiography, so that would definitely be an interesting direction.
Anyway, this past weekend I went on a walk with a stopwatch and a quad-ruled composition book. Since I knew that, from my apartment to the east, the first "room" I wanted was the local bakery, I timed the walk. Three minutes. Thus, the basic unit of distance from room to room would be however far I could walk in three minutes.
2) A foolish realism is the hobgoblin of little designers. And unrecognisably mangled adages. IF convention assumes that the distance between one room and another is flexible: however far makes sense. If a road is pretty much the same all the way along, it's simplest to make it one room even if it's much larger than the distance between, say, the rooms in a house. As for time -- very precise measurements of time are usually not all that important.
How do I convey this sense of travel? There were times when I wanted to produce some text between rooms. That is, I don't want the user interacting with them, or even trying to, because they aren't features of the space, but of the experience of walking through the neighbourhood.
It's pretty common for IF games to contain descriptions of travel in between rooms; unfortunately, the habits of experienced readers tend to mean that any text displayed above the room title is likely to get missed. What do you want your output to look like, exactly?
You can also put in a number of interstitial rooms that contain nothing very different but mean that the player has to keep actively travelling; this is generally considered crap design, although you may get away with it if it's used lightly.
Also, could anyone recommend an IF that is a good study in representing space, or an attempt to map an actual space?
Jacqueline Lott's The Fire Tower
is a representation of a real hiking trail in the Great Smoky Mountains, although it was written from memory. Some time after it was released Jacq and I walked back over the trail and took thorough notes for a putative 2.0 version; that never materialised, and the game as-is isn't as precise a representation of the real-world place as it could be.
Sarah Morayati has designed a system for nonfiction IF, You Are Here
. (See http://www.sparkynet.com/spag/backissue ... .html#here
). I don't know its current status, though.
And of course there's Peter Nepstad's gigantic 1893: A World's Fair Mystery
, which maps out a well-documented historic site.