Cripes. That was a bit of a long quest! Basically, I’ve now finished the Thieves Guild questline (50 more Gamerpoints got, too), but can’t say too much for fear of spoilers. What I will say, however, is there’s a huge trek through the Imperial City sewers, then through “The Old Way”, a secret passage to underneath the palace, then through the palace dungeons, and finally some sneaking inside the palace.
Oh yes, and then you have to get out again.
It took me well over an hour, but ’tis done now. Huzzah! And my saved game says over 76 hours play now. Add to that all the time I’ve spent messing around (like my random guard killing sprees) where I don’t save, and I’d say I’ve been playing well over 80 hours now. Longest game evar!