I have found at least 2 areas so far: a checkpoint near the place where you
fight the Arkham Knight
And the location of one of the crewmembers of firestation 17, near Grand Central Station.
Both areas are filled with turrets, like 5 or 6 turrets at once, combined with several armed or unarmed mooks. I have no idea how to deal with those areas without the batmobile, since the remote hacking device only handles 1 at a time. I have noticed that part of my skill tree is still locked, even though I've finished the storyline already. Is this part needed to deal with these sections? Or is there another way to deal with this checkpoint and this crewmember?