“White Plume Mountain is located in the northeastern part of the Shield Lands, near the Bandit Kingdoms and The Great Rift.” (Erol Otus, AD&D module S2, 1980 and later printings) Dead Gnoll’s Eyesocket is a small cave, the only shelter available in the wilderness. The other locations are not described and can serve as homebrew plot hooks, though they did appear in much later publications.
The shattered ruins of the “inverted ziggurat” below White Plume Mountain, littered with the moldering bones of creatures once bound within glass enclosures, slain by a party of adventurers many years ago (Wayne Reynolds, Return to White Plume Mountain, TSR, 1999, after David Sutherland’s drawing of the intact room from the original 1979 AD&D module S2)
The cursed ruins of Castle Mukos — Who knows what lies within? (it’s meenlocks, lots of meenlocks). This is one of the locations first mentioned as a little detail on Erol Otus’ 1980 map from the original S2: White Plume Mountain, illustrated years later by Wayne Reynolds in Return to White Plume Mountain, TSR, 1999.