Also, as someone who likes to run private quests, you can usually RP a bit with the people signed up and ask to go. As long as you listen to instructions and are willing to work with people most won't mind someone tagging along.
I used to do that with our private runs but I had a bad experience. :(
From what I've seen most people honestly don't treat quests runs as IC unless they're specifically designated as such. They're just loot runs. It's worth a shot just don't get offended if they tell you no, because RP isn't what they're after and/or they're running it to get the loot for themselves.
The first week or so of a new quest people tend to be more IC... but after that.. if they have run the quest 5+ times or way more... or the quest is 2+ years old as all but btb are... it just isnt happening. Though usually people will still be good about letting new players run the show as long as time isnt about to run out.
