Well, it seems that the attacks were fairly quick, but also that they came in waves.
That is, Galactica left the Battle of Cimtar before the attack on Caprica began, and it was over before they made it to Caprica. By then the Cylons had moved on to other colonies (apparently attacking 3 at once or so), and Galactica apparently decided that she couldn't reach any Colony in time to save it from the Cylons, so she went back to Cimtar to recover her fighters.
By the time Galactica made the return to Cimtar and then back to Caprica, the first Cylon assault was over, and the Cylons had pulled back to regroup before returning to mop-up. Galactica hastilly rescued as many people as they could take and fled, then the Cylons returned (and Baltar gloated).
All in all, it seems to have gone fairly quickly.
That said, I do think some stories could be set during this time. The problem is that you need to keep the time VERY compressed: from first attack to Extermination Wave should be at most a couple of days, and more like 36 hours. However, that Extermination Wave may take days or even weeks, as the Cylons did not seem to have any "human-detectors" better than the "Mark I Eyeball".
They're just wandering the countryside shooting any paople they see (or rather herding them together for execution).
So, there's another period for stories to be told in: while the Cylons are hunting and killing the survivors.
