No, our group that I DM'd did not have a 15-minute workday. There are several reasons why we didn't that I can pinpoint to:
1) The party has always been about 6 or 7 players, so they have a bit more strength at their disposal.
2) First monsters encountered were the kobolds, and most of them were handled via roleplaying (intimidation and awe). The wizard only blew one daily spell (Sleep) in these series of encounters, the clerics were fine.
3) Second monsters were the goblins, and they were handled relatively easily several groups at a time, and the ogre that was brought into combat by the goblins was bribed to stand down. Damage suffered was mainly fixed via Hit Die and one or two of the clerics' heals.
Party went back to town and rested.
4) Within town the cleric with the Healer theme made several Potions of Healing and another Healer's kit. I also reconfigured the asinine armor cost table to more closely match the 4E one (because the costs for armor in playtest table is just stupid) and thus several players could upgrade their armor to the next level and get another point of AC out of it.
5) Upon returning, the hobgoblins were dealt with over several combats. Spells were diligently used (the wizard relied on MM and Ray of Frost more often than blowing Sleep and Burning Hands, and the cleric of Moradin used only one spell in any specific fight)
6) The gnolls were mainly avoided using skill work.
7) Several of the undead that roamed the valley at the end of the day from the cultist' caves were picked off by Magic Missile / Radiant Lance, as well as applicable avoidance skills (running, climbing, jumping, stealth etc.)
Party went back to camp and rested.
8) Party is beginning the foray into the cultist caves, so we'll see how far in they get.
*****
Basically, through the use of skills, roleplaying, and intelligent play during combat (plus admittedly having a bit more firepower than most groups, although I did up the monster counts to compensate), everything that has happened has been "in-game" several hour affairs.