I was going to say, just replace all DestText.Text with SpriteFont.Text (and DestText object's actions with SpriteFont object's actions) and it should work fine, but again, I'm not familiar with SF+, sorry.
Can you describe exactly what part isn't working and maybe I can think of a workaround? Is the text not showing up at all? Do the inputs not work? Can you screenshot your events?
As I said, I accidentally had it set to invisible, but I do have another issue that I'm not sure how to get around, and maybe it's the way I'm doing it.
Should each dialogue be in it's own text file, or could every line of text in the game be in the same file? If all in the same file, how do I tell it when to stop displaying the text?