From another post I put up that applies to what you want to do:
I make sure EVERYTHING is in one folder for my project. I put the project there. I put the still, video and music assets there. I check in preferences that all the Scratch Disks are in the "Same as Project". (All but "Media Cache" will remember from project to project.)
First, I set up a basic structure on the C: drive that looks like this:
I put copies (not cherished and protected originals) of the files I intend to use in the Asset folders. Explorer or Finder work, but my favorite is using Lightroom because I can use so many rating, grading and collecting tools for both photo and video files. A somewhat hidden tool in Lightroom that makes this work this is the "Export as Original" feature. I don't use Organizer so am not sure how that would work for this.
Next, I start a new project in "Hawaii Vacation" and Premier Elements builds the rest of it's structure withing that primary folder. This is the best moment to double check the Scratch Disks and reset Media Cache if necessary.
Once it is set up, I do the Add Media step and get started.
At any time I can move the complete project, assets and all, to an external drive (of any letter) with Explorer. Normally it is for archive purposes. If I want to work on the project later I can move it back to the C: drive or to another computer's C: drive. If that other computer has a (second) installation of Premier Elements, I can work on the project.
I started this work routine a few years ago to take advantage of a relatively small laptop SSD C: drive that is speedy enough to make video editing a smoother and faster process. Output rendering is especially nice with everything on a SSD.