I've waited for a really long time (fast traveled between hold cities frequently) and completed numerous other quests since the pre-requisite quest, yet the courier won't show up. I've tried some console commands, but none of them seem to make the courier appear and console commands to advance the quest won't work unless I've received it first. Is there a console command to fix this? Any other suggestions?

You might have to be a certain level for that one.

I don't think level is the problem as I'm currently level 41.

EDIT: I should add that I had to use console commands earlier to fix a bug at the beginning of "The Man Who Cried Wolf." I couldn't start that properly either because Varnius Junius (the guy from dragon bridge) wouldn't talk to the Jarl to start the quest.

yeah I would agree. Trying talking to all the people in the court. Maybe you also need to do a few radiant quests in Solitude to raise disposition. Did you get the quest from the Jarl yet?

I haven't done many quests in Solitude yet so I'll give that a try. Which quest that the Jarl gives are you referring to?

The first bard's quest interferes with the Man Who Cried Wolf. The quest wouldn't start for me either but as soon as I completed the first bards quest ( I mean the entire quest, until your journal says it has been completed) the Man who cried wolf started. It's lazy scripting: there was a scene in the bards quest in the blue palace and instead of making a conditional check only for that scene (quest stage) it seems that there is a script checking if the entire quest is running. Dunno if it applies for the Wolf Queen quest though or if another quest was supposed to be launched by the script initiating the Man Who cried wolf (by the way, the trigger for that quest was located right at the top of the stairs of the Blue Palace...at least this is where the variable to start the quest was changed).

Are you talking about the quest The Burning of King Olaf? I did that quest before doing The Man Who Cried Wolf, but I still ran into the issue of Varnius Junuis just standing there.

And as for doing missions in Solitude, I've completed a few more local quests and took the kings horn to the Shrine of Talos. Still no luck. I sent Bethesda a message on their site.

So after playing the game for 8 hours after The Man Who Cried Wolf quest, the courier finally showed up outside of solitude. I have no clue why it took him so long/what I did to fix it. Thanks for the suggestions.