Dropbox is a fine alternative or supplement to Google Drive. You set up a top level folder of everything that you might want to move, data, documents, etc. Then set that drive to be duplicated on the internet. You can work locally. Files will be synchronized with the internet copy the next time you are connected. It also does not matter if you decide that you want to switch platforms, Windows, Mac, even Linux, not that you care about that option.
Much easier than using USB or external drives.