It is possible to nest runtime folders within the Poser Library, I have seen this.  But it can completely screw up the Library hierarchy and function.  

Firstly, if you indeed only have one Poser install (and Poser installation gives you the option to add the 32-bit version during it's initial loading) than you should only be installing the matching version of the DSON script.  So, 64-bit PP2014 should only contain 64-bit DSON.  One DSON install for each version.  

Secondly, your Genesis Starter should have, basically, 2 types of files: 1 DAZ core zip and 1 Poser Companion File (PFC) zip; DAZ core is intended for DAZStudio and PFC, of course intended for Poser.  Regarding the DAZ original zip files, they all contain a top level folder entitled Content, and within are the necessary folders for each application.  The DAZ Install Manager (DIM), when used correctly, will extract the support files from within Content and place them all in their correct places in each intended application.  The Content folder itself is never transferred, only discarded automatically.  If you manually unzip each file into a temporary folder, you will need to open the Content folder and manually transfer all the folders within to their final  destination.  NEVER transfer the Content folder itself.  If this explanation is unclear, let me know.  I will illustrate it for you.

Thirdly, for the sake of easy management and organization,  create two new folders, 1 for the DAZ Core content and 1 for PCF content and call them anything you desire.  I call mine My Library and Genesis, respectively, it doesn't matter as long as you know which is which.  Transfer folders to their intended locations.  Next, link these new folders to the Poser Library; yes, that includes the DAZ Core folder which has it's own runtime which may, or may not, be empty.  This is to guarantee that Poser finds all support files when it scans runtimes.

And that should about do it.  Any problems understanding or working this out let me know.

"Does Runtime have the to the highest folder in the folder tree in order to be seen by Poser, or can you pick a Content folder and Poser sees the Runtime folder inside?"

Yes, Runtime must always be the highest folder in the hierarchy for everything to work properly.