[Enlil-An]

It never says Christ was 2 years old when the wise men arrived at His doorstep.
It says, that after Herod realized his wise men weren't going to return at all, it had been two years since Christ's birth.

You should read it again. The wise men were the ones who told King Herod that the star appeared two years previously. When the wise men find Jesus, Matthew specifically refers to him as a "young child". After the wise men leave, then the Lord warns Joseph to flee into Egypt.

Matthew does not say that Joseph and Mary are from Bethlehem.
(He does say that Joseph wanted to put Mary away privily, and I would not be surprised if they left wherever they were FROM [where people knew her, and knew she was unwed/pregnant] and went to a town where people wouldn't know of her condition)

Then why did they return (your words, not Matthews) back to Nazareth? Did they assume everyone in that one-horse town would forget the whole unholy affair after a few years?

Luke states:
39 And when they had performed all things according to the law of the Lord, they returned into Galilee, to their own city Nazareth.

Which contradicts Matthew who says, "he turned aside into the parts of Galilee: And he came and dwelt in a city called Nazareth". Compare the wording of the two.

But it doesn't say how long it took to do all the things, what all the things were, and where they were currently dwelling before their return.

Yes it does because it says, "when they had performed all things according to the law of the Lord" and since we have the law in Leviticus, whe know that it wouldn't have been more than a month - nowhere near two years.