How can I port from the depths of the underdark - not even near a "portal" - to my camp (or anywhere on the map) and then rest? Almost like the daft NWN1 systems where you 'knelt' down to rest (*literally outside the next encounter*) It simply doesn't work for immersion - this was commented on a lot in EA, there was a megathread too...but I suppose for those who prefer convenience over immersion, it doesn't matter. Sadly that doesn't work for me - I want an experience similar to table top in terms if tension.
The map of the camp changes based on where you are. So I'd assume that you don't port from the depths of the Underdark to your camp, but instead, you camp in the depths of the Underdark. Probably not right where you're at (most of the time), but a "safe location" you found nearby, where Withers, the hirelings, and some other camp followers you have picked up along the way have secured the area. And realistically, such places would exist most everywhere, otherwise, travel and trade would be impossible.
Of course, that doesn't fit all situations. It makes sense if you are wandering around the Underdark, thumping some random critters and such, but not if you are busy wiping out the Duergar, goblins, or Gith. Those are collectives of intelligent critters, who would A) notice that some of their fellows aren't around anymore in that 8h+ and naturally blame the outsiders, B) hunt for you to get payback and/or C) Prep stronger defenses for when you came back. But alas, the limits of computer games.