It took me an hour or two to move all of the folders from the Dropbox top level to the 4 folders I had created: one for work, one for genealogy, one for everything else, and one for unassigned files (the inbox).
As I moved items, I was able to delete a few of them when I recognized them as outdated or otherwise no longer needed. But there were some remaining folders that appeared that I decided to leave at the top level.
One was a folder I share with George. Because it contains a mix of genealogy-related content and home-related content, I decided to leave it where it was.
Another was the Apps folder, used by a number of software tools to share data between my desktop computer(s) and my mobile devices. For instance, it contains a RootsMagic folder.
There was also a Camera Uploads folder, which was used by Dropbox to move items taken by my mobile devices. Because I couldn't guarantee that my photos would all fit in the category of genealogy or be work-related, I decided to leave it at the top level, with a scheduled project to go through it at a later date and move the photos to appropriate folders.
Because I wanted my main folders to be easy to find without the need to scroll, I put an exclamation point in front of each one, and two in front of the Inbox so that it would remain first.