I had a section of the map that I found, which had a LOT of notable locations, some stacked two or three deep.  I'd guess I 'harvested' about 30-50 of them in short order, and left the higher level ones behind for later.  About every 2nd or 3rd square in a 15x10 section of the map.

This is around Fall 175 or so.

Magnar had a whole bunch of these next to his capital, which he wasn't bothering to harvest.  Porcipinee was also right next to this 'trove' of goodie huts and was also ignoring them.

I'm guessing there's a random seed formula that's not working right... most of the rest of the map was pretty barren goody hut wise (one every 20-30 squares or so).  I have not explored 'below the equator' yet.

Mine were concentrated almost to the right edge of the map, just above the middle, and continued about halfway to the top of the map then petered out, if that helps.