I have tried COCing to whiterunorigin and whiterun, but to no avail. When I do COC out of Dragonsreach, I encounter a generic dragon, kill it, but nothing happens. Any suggestions, or it is time to put this mess away and wait for ME3 to release?
BTW, ALL of my characters have encountered the infinite load screen, eventually. The first time I encountered it was during my initial playthrough, prior to having installed any mods. That was on patch 1.3, I believe. Knowing this was a Bethesda title, I waited for the first round of patches. Looks like I did not wait long enough.
Current playthrough has some texture mods, and a few added items, but nothing that should be interfering with these area transitions. Things are particularly buggy in Solitude and Whiterun, neither of which have specific mods applied. Can usually bypass by COC, but it seems the trigger for this particular dragon is keying on the exit of Dragonsreach??
I am old enough to have played through every Elder Scrolls game, and remember dealing with Oblivion, but this is the most frustrating game I have ever played! So much promise squandered, it's aggravating.

I've tried the 73 hour wait as well, and it seems to work sporadically. Still getting this in Whiterun and Solitude. My workaround has been to player.moveto the quest giver, complete the quest stage, then coc to riverwood. If I do this, I seem to be able to fast travel on to the next step, so long as I stay away from Solitude and Whiterun. This gives new meaning to the old phrase, "We are all beta testers." Haha