At this rate I'm going to have to passwall the entire dungeonYou will never
have to use Passwall on a dungeon. It can be handy in the MQ dungeons, but in the case of random dungeons, Passwall is overkill.
Any clues as to what the room the monster (err, the guy holding her) is in will look like - size, shape, features?It's random, so, no, sorry. If you do get near the monster, you will get a message on the screen saying, "You sense the [monster] is nearby." Then you'll see the monster and probably the hostage as well.
Edit: It looks like the earliest save I have is 2 or 3 weeks after the quest was given - it's possible that I've travelled to the dungeon once and returned from it. Would that break the quest?Probably. But the log tells when you got the quest and how long you had to complete it, and the status tells what day it is now, so you can do a calculation on that and see if you've blown it.
Actually, it's possible that I've actually completed itYou'd know if you'd completed it; first, you'd have had to click on the hostage near the monster, who would then tell you to hurry up and get back to the quest giver, and even specifically give you a date (how do they know?
), then you'd have had an icon on your screen representing the rescued hostage till you got back to the quest giver.
but that doesn't explain why I'd have gone back to the dungeon (except for loot) - is there any way to tell if the quest is still active?Do the math like I described above.
I've just loaded the old save and discovered that it's possible to get a new quest from the save questgiver - does that mean that I completed the first one?Possibly. It could also be that it's a save from prior to getting the quest (easy enough to tell). Or it could be that you did in fact blow the quest and you're getting a new one; Arena is not like MW, or even DF. Quest givers have no memory of you having blown or succeeded in a quest.