If I could wish for one thing for Layout, it would be for a command to “package” export a project along with all of the referenced files — much like InDesign’s “Package” command, or V-Ray’s “Pack Project” command.
This would allow an entirely completed project to be archived to another disk, or transfer an active project to a different computer (i.e.to a laptop when working remotely for an extended period of time). Collecting all files manually can be a time-consuming nightmare for very large construction documents. I think it would be great if referenced files were to be linked using a relative paths instead of by an absolute paths — that might streamline the process to manually collect all referenced files.
Another suggestion would be to have the ability to sort referenced files within the Document Setup panel by document type and also by document name.
You can really do that already. The LayOut file is just a .zip file with a different extension. Copies of all the referenced files are included in a folder within the .layout file. 7-Zip will open a .layout file natively and maybe other unzip utilities will do it as well.
In a sense, one would only have to archive a LayOut file for a project if there us one Layout file (many to one)
If the original content files are gone or the path has changed you can do as explained in the help article.
When creating multiple layout files from one SketchUp model (one to many) it becomes more difficult because there is no connection or meta data attached to the SketchUp model (eg. This model is used in this or that LayOut file)
So one might even consider to create a LayOut file first when setting up a project, instead of starting to model right away in SketchUp, using it in a project monitoring way.
Btw. the references file paths should be relative already.