And re using Khan Academy (or Bio for Dummies, or whatever, et al) before jumping into the postbacc-
That is something I've thought about. But 1) I don't want to burn myself out before even starting and 2) I feel like it's the same at pretty much every school, but depending on the prof and the textbook some things might be emphasized more than others. This is the nature of all survey courses I think. In my intro bio class it seemed like the class had more of a focus on molecular bio than say cell stuff compared to some friends who took prereqs elsewhere. But I dunno.
I'm pretty much starting with a blank slate so I might skim an AP Bio/Chem book or some similar study guide to get the 30,000 foot view, but not get too deep into the weeds.