I don't really know how to do any of the advanced stuff with Quest, but yeah, I think moving the player would probably be the simplest way and keep you from having to deal with them trying to interact with things in the room they were in before. As for making text disappear, I
think that's what they're talking about in [rul="http://forum.textadventures.co.uk/viewtopic.php?f=10&t=4703&p=30980&hilit=makign+text+disappear#p30980"]this[/url] thread, if any of that makes any sense to you.
And fwiw, this is a really cool and unique idea for a puzzle, I like it.