I watched a video on Youtube, and it seems pretty straight forward and simple. You can always carry a couple of boxes of bags in your BOV.
The main problem I see with it is that the bags will deteriorate with exposure to the sun (UV). But, this is a fairly simple problem to solve. Once the building is up some adobe or mud on the outside will keep the UV off the bags, it will also seal any gaps and make the building even more draft proof.
Honestly, how much simpler can it be? fill bags with dirt and stack making sure that the next layer overlaps the joints between the one below? And tamping the layer down before putting on the next layer? Two feet or so of dirt is a decent amount of insulation between you and the elements.
And tools? A couple of shovels, maybe a pick axe, and a soil tamper are your tools. A stand to keep the bag up as you fill it would be nice, but you can build one when you get to where you're going to build.