I think the smoking mountain appears again in canyon of shiny stones. It's a volcano that mainly just spews smoke, but does lava now and then.
I don't think they said where the sheltering grass is, it's a place, like mentioned before, a field of tall grass that is good for young ones, like the gang, to hide in during hide and seek. I don't recall what was going on during it's appearance.
Many places of the great valley they don't really say where this is in relation to that.
That is a good idea. Maybe for some folks someone who is an expert in LBT and the great valley can do a short sort of encyclopedia of lbt places with a brief description.