You may notice there is incomplete information on Disney's FastPass+ system in the 2014 edition of the Brit Guide to Orlando. At the time the book went to print, Disney had not yet released details about FastPass+, so we were unable to include specific information in the book.
As of now, you WILL be able to use the system if you are staying offsite (and you will receive full detail if you are staying on site). However, offsite guests will have to wait until they arrive at the park. This stipulation may change at some point.
Please use this link for Disney's information on FastPass+: