Google-drive – Navigate to last file in a folder on Google Drive

There's Etherpad, which is a GPL collaboration verion of Google Docs. There are various example implementations which protect the privacy of your documents, although privacy isn't the issue.

Google just announced that now they included a the search within folder feature.

From the above link:

You can now search for content in a specific folder in Google Drive. Select the drop-down in the search bar and choose the folder you want from the Location menu, or right-click on a folder and search within that folder. Only folders that are within your My Drive or within Team Drives can be searched; if you have a folder that is shared with you, first add the folder to your My Drive.