http://www.carpepm.net/images/2007_arda.jpg
On this map the locations are not too precise, I'd say, but it gives a general idea. The Two Trees are in Valinor (on the left), the Sea of Helcar is on the top right, way above the "known" map of ME (which is a pretty small thing in the middle of the right continent). Helcaraxe is that dubious passage on the far north, between the continents.