No spoilers please but is it longer or shorter than the dark brotherhood missions?
I did them at the same time, and they are pretty close in length, if anything the Thieve's Guild is a bit shorter simply because you can go through the entire "chain" without having to stop and do the side missions, though you do need to do a ton of side missions to get the achievement.
Opportunity is often missed because it shows up in overalls, looking like work.
Bought Hearthfire. Having a blast building a house from the ground up.
It's certainly a pretty good time sync. What I don't like about Hearthfire is that the three houses are virtually identical, the indoor greenhouse generates bees which is just retarded, and there's no way to upgrade the furniture and things lying around to make it look more ritzy than it does when it's fully built. I'd have more fun with it if the engine weren't massively retarded with placing things in the world... you've got a 50/50 chance of the game throwing your object off of wherever you placed it on when you leave and re-enter.