Well, the only place I can think of is Vault 87, because of the insane amount of radiation.
The Explorer perk does not "find" your locations for you, all it does is put the locations on your map. Until you travel there yourself, you cannot fast-travel to these places, nor do they count as discovered for the unmarked quest Geomapping with Reilly, NOR can you use the Explorer perk to instantly get the Bog Walker achievement/trophy in Point Lookout. EDIT FROM ASKER: I know the explorer perk doesn't find the locations, it just shows you where they are. I have traveled to every location it has showed me, but the game still says i am missing 2 location, and the Explorer Perk isn't showing that i am missing any.