Easiest/Quickest way to backup rootfs (now that I finally got it working!)

So I finally have my 3TB sata drive booting and functioning well on my GFH. Thing of it is that I'd like to make some pretty big changes so I need to backup my existing root file system. i've got plenty of USB sticks that will hold the data, but not the partition. That is, I've got a 20gb root partition, that's sitting at 3.8gb used. I have plenty of 4gb and 8gb usb sticks that I can use, dedicated for the purpose of keeping a working copy of the file system (that I could restore via the rescue system that is in NAND)

Can anyone advise me on a simple / quick solution to back it all up to a USB stick that I can plug in to the usb port?

The easiest tool to use for this that I've tried is Acronis. If you have Windows VM (which I did) or Windows box, you can clone the entire HDD boot drive to a USB stick and shrinking it at a same time. Of course the HDD has to be taken out and plugged into a Goflex USB base or a HDD dock.

I can't use the USB3 base because it does some 4k sector conversion magic so the drive appears differently than when it's used over SATA directly.

I figured it would be pretty simple because copying the files should be sufficient. I mean I don't need to copy the partition fully or anything right? I mean I started from a tarball, so can't I just make my own tarball of the filesystem? I just suck at the commands necessary to make it :(

guess I should have looked around on my own. Wasn't too hard to find something that will do nicely:
https://wiki.archlinux.org/index.php/Full_System_Backup_with_rsync