The best possible way is to go with Snapshot, as you already done.
Better than this you can't really find.

However, you need to do changing IP address for site and home URL in WP Admin, as suggested by Codex.
You can't really break to much, even if you break you can restore snapshot once again.
That should do the job.

If you read this guide, it appears there are many ways to modify your sites default login url/ip address.
You can either ssh into your second server you created using snapshot restore and modify any of the files like wp-config.php or whichever method you can do easily.
But if you just need a backup of your website to restore just in case if something goes wrong, you can enable backups in your droplet (if you haven't already). With this you can restore your sites to any of the weekly backup available. You don't actually need a second droplet for a single website backup.
You can also manually take snapshot everytime you update the website's contents.
I do not know how much server administration skills you have, you should also consider securing your wordpress installation and your whole server in particular as wordpress is one of the most exploited platforms.