I don't rush at all, I do everything pretty thoroughly. I saw a guys walkthrough on Youtube and he spent roughly seventy 15 minute long episodes and at the end? He was level 16! The kind of dungeon that would take most people 20 minutes took him like an hour and a half because he took it so slowly. SO SLOWLY. And I have no problem with that if you're gaining something, but creeping at the speed of a snail through Pinewatch doesn't give you anything. He found 1 bandit and took about 5 minutes deciding how to engage him. I mean, come on, it's 1 bandit.
So if you were that guy, yeah, 600 hours sounds realistic. But that's not a satisfying way to play, taking 10 minutes to walk from point A to point B and gaining nothing in between.
No no no no no. That's not the point. I'll tell you what, I've probably done what seems like absolutely everything on one character and I'll still play. Finding things, doing new things, is what keeps you playing.
For example: I'm maybe level 40 and I've been playing my new character since a bit after Dawnguard came out.
Now, I'm not one for rushing, and like you said, I take the dungeons slowly. Despite this slow playstyle, I find a lot of time to play. Eventually I'll run to the dead end of my particular playthrough (archer) and I'll start my second playthrough with that same character: an illusion mage (I'll still use the bow). Understand that I don't start this until after I finish all the main quests.
This is my play order: (leveling up throughout)
- Main Quests
- DLC Quests
- Shouts
- Daedric Quests
- Main Misc. Quests
- Explore
This usually takes a lot of time just to complete! After this, I'll start collecting...
Misc. Quests follow this. I also not only develop my own character, I develop my follower. The crafting skills are very fun to develop throughout the game.
Like all characters, I'll eventually become very powerful. I then stop using powerful weapons and armor and focus on the more subtle details of my game: aesthetics, clothes, etc.
Don't forget to play on Master for the ultimate challenge.