no settlements or towns aside from Hydro Quebec's settlements for workers (these are private and are not open to the public - they will kick you out)
I've recently watched a Youtube vlog made by some tourists who went there on motorbikes and they stopped just to have a look at one of the Hydro settlement, they were invited in, given coffee and when they mentioned they wanted to find a spot nearby to pitch a tent they were told they could sleep in a hut that was unused at the time. So I guess they are indeed very nice with passersby, I guess they just have a general "rule" because they don't want travellers to rely on them.