This will take a lot of resources. The minerals and wood is easy enough to come by as you explore. Sometimes you can even buy the various kinds (possibly the tablets I'm about to describe too). The only thing you will have a challenge finding are the ancient tablets that each upgrade requires. These are hidden in hostile areas shaped like a hangman's noose all over the map. You will only know when you are close enough to view the area goals, unless you buy the time saver for your map that shows them. You don't even have to clear each area, if you are stealthy enough.