Short answer is there isn't a reasonable way to go from Presenter to YouTube. The Video Express tool will capture your screen and webcam video and audio, but not the audio in the presentation. It can output to MP4 for upload to YouTube though.
Presenter itself doesn't output a video, as I'm sure you are aware. So converting the collection of files to a video is no small task. Captivate may be the easiest path since you can import or recreate your PPT content there and then re-import the audio and video into Captivate. Then there is an option in that tool to output to MP4. While this may be a huge pain for this project, consider using Captivate from the start for future projects if the output of a video file is your end goal.
Unfortunately, my worst fears are confirmed. I hope Adobe doesn't bother with another upgrade of Presenter until they can correct this hole. I'm a teacher and I bought Presenter thinking I could make really nice lessons and publish them. No use using it it since I can't upload to Blackboard or YouTube.
Not sure it is a hole. The Presenter has always been a simple tool with a limited feature set. The rule of thumb, from my perspective at least, has always been if it can't be easily done in Presenter, use Captivate.
And Presenter can be uploaded to Blackboard or any other LMS.