IMO, PBL doesn't really exist in the preclinical year at Duke. We have 2-3 labs a week of 2-3 hours each which sometimes involve light "pimping" or working with small teams (dependant upon your lab instructor), but nothing like what other schools trumpet as PBL.
To give you an example of this week's 1st year schedule:
Mon: 9-4, 6 lectures
Tue: 9-4, 4 lectures, 1 lab
Wed: 9-5, 1 lecture, 1 lab, and a few hours practicing physicals on wards
Thu: 9-4, 4 lectures, 1 lab
Fri: 9-12, 1 lecture, 1 lab
And this is as intense as it gets. Labs are mandatory, but you can download/stream videos of lectures from your home, the library, your fave cafe, or even the beach.