Rclone is now included in FreeNAS. 

Then follow his guide to install gdrive:  https://rclone.org/drive/

Another guide: https://bytesized-hosting.com/pages/rclone-gdrive

Once setup it should look like this: 

cronjob for rclone I use: 

rclone sync /mnt/v1/media/ gdrive:Media/

Basically if I add or remove any files in my /media/ folder where I keep my Movies/TV it will add/remove it from my gdrive account and vice versa.