My world is an underground mine. I have many interesting rooms, but I'd like to spread them out. When a user enters a new room, the room name and description ar printed. This is my first game and I don't have much creativity. And they're not really rooms, just passageways (and perhaps one with a very minor detail). So going from room 1 to room 2, there is some distance.
[1]---------[2]

Should I just say: "You continue along the passageway"? Should I indicate which direction you can travel? If a user can't move in a direction, I just print "Blocked"

I love using the {random: description 1: description 2: description 3} here for this stuff exactly. It gives a little flare to what otherwise could be a monotonous room sequence.

As for your exits, just have Quest handle that internally. Also, I 100% of the time would indicate which possible directions are possible. It would be awful to try and guess which directions are possible exits. IMO.

Xan beat me to it. I've been writing games on squiffy for some time now and always include random descriptions to each room. The best way to do this is to write your description, then (if you are unimaginative, as you say) cut and paste those words and run the thesaurus on them. Pick your favorite words and use them in your description group. Also, think of anything that can make it unique. Even in the underground realm, you could comment on...

temperature
smell
illumination
distant sounds
incidental wildlife
and even how your character is feeling (frightened, nervous, jittery).

Hope it helps!

Thanks yes, I like the random ideas