Essentially, it would detail the quests completed, dungeons cleared, crimes commited, skill levels gained for each day. My character has spent 337 in game days, and I would just be curious as to how long he spent doing each of the guilds, random questing, stuff like that. I would really like to know how long he spent doing radient quests for the thieves guild, things like that. I mean, it didn't feel like a long time, but considering I was fast traveling everywhere, it may have taken over a month or two of game time.

You mean like the one in MW.. or simply a sort "Captain Log" to see your activity?
Personally i'd like a MW sort of Journal as it doesn't the objectives as simple as the OB and Skyrim