After connecting the N7 to my PC, I created a folder called Books and placed my files there. Most of my eBooks are in the .mobi format, so it took a little trial and error but I tried and love the free Cool Reader app.
I am hopeful one day Google Drive will be enhanced to allow my eBooks to be opened from there. It allows a file to be "pinned" or stored locally on a mobile device, but you can't choose the location and I've been unable to get an eReader to access them that way.