Here's my scenario...
I had Google Drive installed on a Windows platform.
Only items I place in the Google Local Drive get synchronized with the Google Cloud Drive.
I have files outside of the Google Local Drive that I want synced with the Google Cloud Drive.
Hard links only copied the first time; subsequent updates to the files with hard links did not get synced.
With Insync you select the folder you want synced with Google Cloud Drive via context menu (right click Explorer menu...super easy).
Insync creates a link from your external folder to your Google Local Drive, which is then synced with Google Cloud Drive.
Subsequent changes to the files are now copied to Google Cloud Drive.
Insync mostly solves the above problem.
I have one remaining problem with GoogleDrive+Insync:
The above solution only syncs at the root Google Cloud Drive. Ideally I could select which Google Cloud Drive folder to sync with my external folder.