Will outside places repopulate overtime again? For instance a camp or perhaps a nercomancer study location?

i think they do after 30 days.

IMO, 30 game days is too long for certain places. Sometimes, not even a Radiant Quest could force a location to spawn new enemies (as such was the case with Valtheim Keep, place never respawned, ever. And any radiant quests that involved that area were unable to be completed because nothing respawned there). I even waited 30 days, in a different cell, and that area still didn't respawn.

I guess it's hard to balance, Oblivion's 3 day respawn time was too fast, but Skyrim's 30 is just too long. But of course, this is just my opinion.