The girls have gone away

[Ridgeplate]

I second the opinion to drop the repetitions. They inturrupt the flow.
I also agree with the idea of dropping "lass".
Maybe:
I have waited too long for Someday
and I depart, in search...

In addition, I question the capitalization of "Someday". I gather that you are trying to add emphasis and added meaning to the word, and it's no stretch to see where you are going with it, but the lack of additional puncuation in some of your lines is not, in my opinion) made up by the capitalization. Altered line breaks may also accomplish this.

Consider the following possibilities:

Perhaps, someday, will return back home
or
Perhaps someday,
will return back home,
+
I remember, someday, so dearly,
or
I remember,
someday, so dearly,

As with much poetry, I may simply be missing your intended impact, and mean no presumption with my suggestions. You're on to something here, so please, keep it up.