question about the place they called mashu and dilmun

by Joey
(Makati City, Manila, Philippines )

I am reading the Epic of Gilgamesh and Atrahasis. I was so amazed to know that they are the first scriptures older than the Bible. My question is this; Where really is Dilmun and Mashu?

I have read wikkipedia and other articles, but it leaves me with more questions than answers. If Mashu is in Northwest Lebanon, as per Jeff Tigay, and Dilmun is in Bahrain, would it be possible for Gilgamesh to travel to Iraq, Lebanon and Baharain, and then come back?