Is it flaky/inconsistent internet service or is it more like you’re out in the woods somewhere without any service at all?
If flaky service, then syncing your project folders via something like Dropbox is a bad idea.
But if the situation is that your internet connection is solid and reliable when you do have one, then you could keep your Scrivener projects in the Dropbox folder and sync them with/to the cloud whenever an internet connection is available. When internet is not available, then you’ll be working offline by default.
Just throwing syncing out there as a suggestion, if you are open to it. Here’s a more detailed post I wrote on syncing a while back. It was written for v1 so the menu paths have changed, but everything else is still applicable.
This is a viable alternative to syncing. I did this myself for a while, prior to moving to Dropbox and syncing. Your Scrivener project folders could contain hundreds of files, so be sure to use zipped backups for the transfers, as there’s much less opportunity for copy errors with one large file vs. hundreds of smaller ones.
The main challenge with this approach is keeping track of the latest version and what PC it’s on. Enable the option to include date in the auto backup name to help deal with that.
I assume you mean using a cloud service for transferring zipped backups instead of an external drive? Sure, you could do that. Email works as well. But these options require an internet connection, and if you’ve got an internet connection, why not just sync your project files?
Best,
Jim