I'm in the same boat and would love to hear others' opinions, but I'll offer what I've been doing so far. I purchased USMLERx at the beginning of second year and got through about 68% of the bank during my first semester (did a few questions every night, skimmed relevant FA sections - nothing heroic). This semester, I've been working through the Kaplan high-yield videos provided by my school along with FA reading and Rx / Kaplan qbanks.
So far, I've been trying to dedicate 1-2 hours per day to boards during the week and maybe double that on weekends. Obviously, my schedule will be more dedicated to boards prep as the semester winds down, but that's what I've been doing so far.