I'm not sure if this can be done with workflow or workflow scripting (I can't find enough of a reference on Workflow scripts) 

I'm trying to use workflow to replace an old SDK script which iterates through all documents in SourceFolder moves them to their final destination with the following logic. 

• Check to see if there is an existing folder in the DestFolder with the name FileNumber (Which is a metadata field). 
  • if the folder doesn't exist
    • Create folder with the name FileNumber
    • Rename the doc to FileNumber
    • Move doc from source folder to destination folder. 
  • if the folder FileNumber exists (we'll assume it will also have a document in it named file number based on the logic above)
    • Does doc FileNumber in destination folder have any linked documents?
      • If True: send an email with names of linked documents (or doclinks or just a link to DestDoc) to advise data entry of additional work to be done. 
    • Prepend sourcedoc to doc FileNumber in folder DestFolder/FileNumber
    • Delete SourceDoc

What I can't figure out in workflow is how to access the metadata fields to get the FileNumber to use to create new folders and documents. 

I also can't seem to find any documentation on exactly what classes / methods are available via standard (non sdk) workflow.

I'm using 8.3 right now, but would gladly update to 9.1 if it's a matter of doing that for the required functionality.