Considering the Underdark is at LEAST 10 miles below the surface (going as far as 26 at least too) with the Upperdark still above that, it does feel really silly you can just walk there just like that, from several locations. And then do a quick jog back to the camp that is somewhere outside at the static location to sleep.

Though not just the Underdark, but the entire map feels like a themepark where you just go from special event/special location to the other, all nicely packed together. It also makes it all the more hilarious how the goblins cannot find the druid grove, a few minute walk from their camp would get them there.