Firstly, regarding tinkerers, the Collector gleaned from the elder that there was minimal risk so long as it did not travel too far south.
Sufficiently far south, the temperatures became increasingly less extreme, allowing certain species of evergreen trees more resistant to the cold to sprout and flourish. These conditions induced the growth of a sprawling forest stretched as a thick band across the southern boundary of this land, and here, the majority of tinkerers made their residence.
Regarding the number of the tinkerers: there were ten tribes of native tinkerers in total in this area, this land titled as "Fjall".
These tribes possessed adherence to warrior culture and simpler ways than most tinkering civilizations, and this in turn along with their harsh environment caused their individual numbers to be low but every individual to be of a higher grade than the average human specimen.
Went ahead and added a map of Fjall, you should be able to see it on the maps and locations chapter!