Have you hacked 4e at all?
Not really, no. We're playing pretty much straight from the rules plus errata (except no errata to CaGI - it was fine as written!). Two players have custom themes, and in a few places power source prereqs have been tweaked to smooth over some multi-class bumps.
how many hours of play is the above adventuring day?
From memory, the Orcus scenario took two encounters, then there was dealing with the aberrant orbs and kraken who came through the Abyssal rift, then I think two sessions in The Barrens. Our sessions are 3+ hours, so that would be 15+ hours of play, and around a month-and-a-half of ingame time. (No long rests on the Abyss unless you can find somewhere to protect you from the horrors of the plane. Is that a hack?)
We are relatively slow-placed in our play, being a group of middle-aged guys getting together on a Sunday afternoon.
When I was still running 4e my adventuring days tended to be much shorter than pemerton's. I tended to 2-3 combat encounters per extended rest, leaning more towards 2 than 3. I despise filler though and never really had at level encounters. Our games are unusually talky though - we tend to have a fight break out roughly every 3 sessions or so no matter what game we play.
I also don't like filler.
Our game is less talky than what you describe - we have had combat-free sessions, and social-only sessions, but they're not the norm. A lot of our characterisation and plot development happens during combat - the invoker calls upon Pelor to help him control the Sphere of Annihilation, or the fighter/cleric decides to side with Osterneth against Kas, an chooses to take on the divine portfolio left vacant by Torog's death, in order to help him beat Kas in melee.
It's not great literature, but I'm fairly happy with how the game has gone. Definitely the best experience I've had with D&D, and I think a very good RPG provided you don't mind combat as a pretty prominent site of conflict resolution.
