Does email-to-SMS work for any SMS location?

Hi.

If I live, let's say, in the North of The United States, and I want to send a text message (from my email, if that makes a difference) to someone in the South of The United States and as far as the other coast of the continent, will that person:
a) get the text approximately around the time when I send it?
b) get the text when she returns to where the coverage is guaranteed to work? -or-
c) never get it unless she happens to be in the covered zone when the text message is delivered?
(I know how to do email-to-SMS, and I've done it before, so that's not an issue.)

I have to ask because I never had a cell, and I'm not interested in them, so therefore I don't exactly know how these small things might work.

Could someone enlighten me, please?

Thanks.