My specific question is how to set up Google forms to allow a two-part answer. For example, which of the following books have you read and how many days did it take you? So you would have many book titles and if you clicked any of them, another field would pop up and allow you to enter the # of days it took to read. This will save so much more time than asking someone to enter in every book and then a follow-up question of how many days.
Currently there is no real way to do this. The only thing I could suggest is a list of check boxes with numeric input fields correlating with each box, with the hope that the user won't accidentally or purposefully enter bad data into the numeric fields corresponding to book he didn't read.
If you are making this for your own, self-hosted sited. I'd look into something like RS Forms Pro, which makes creating forms and manipulating responses much faster and easier.