If you recently picked up Far Cry: New Dawn and was curious on how to upgrade Prosperity, look no further. Ubisoft released a video giving you all the information you need. However, the fastest ways I acquired ethanol was scavenging an outpost upon liberating it until defeating all the difficulties associated with it to get the most ethanol available. Expeditions are a new addition and are not only extremely enjoyable, but are your main source of getting materials needed to craft new weapons that will need to be utilized to overcome the more difficult outposts.
