Working at least partially from memory:
Session 0: ~7 hours
#1) 105 minutes, 500 XP, 2 crits, 0 dailies, 0 action points, 9 rounds vs 3 skirmishers and 2 artillery
#2) 45 minutes, 550xp, 1 crit, 0 dailies, 0 action points, 8 rounds vs 3 skirmishers and 1 trap.
#3) 70 minutes, 675 xp, 2 crits, 1 daily, 2 action pints, 8 rounds vs 4 minions, 2 artillery, 2 brutes, and 1 trap.
#4) 90 minutes, 850 xp, 0 crits, 3 dailies, 4 action points, 10 rounds vs 2 artillery, 1 skirmisher, 2 soldiers, 1 artillery (leader), and 1 trap.
My party consisted of a cleric, a wizard, a druid, and a paladin. My target time per session is 6-8 hours, run twice a month (less this month). This is "Session 0" because I ran the back-of-the-DMG adventure as a "practice session"--my players are all new to 4e, or generally unfamiliar with D&D, and one had never even heard of a roleplaying game before, so I wanted to give them a chance to try out character options before "finalizing" them (I'll let them change stuff around anyways), try out the rules, and get a feel for the game.
If you're familiar with the adventure, you'll notice we only got to four out of five encounters--we ran out of time. If you use the Lord Warden hook, they get the item they need in the fourth encounter anyways (you might be able to tell I did very light prep for this, though it still turned out great), but since this was a "practice session," the party never actually decided to continue onwards or to head back. So, I can use this a plot point later on in the "main game" since they're using different characters.
I'm not so sure they would have survived the last encounter anyways--I forgot to scale the encounters for a party of four. I had a fifth player lined up that cancelled, and it didn't occur to me that I needed to scale the adventure. Oops! The fourth encounter was relatively close, but the party got through it okay. I'm glad I got to teach the players the dying rules, and the guy with 2nd edition experience now respects kobolds.
In light of all that, the players and I all had a blast! I hope to get to our "main game" in short order.