From a timing standpoint, wouldn't be option one?
-Play ever my heart rises from your draw deck
---preform when you play actions
-shuffle your draw deck
Each time something allows you to play/take a card from your draw deck, you must shuffle your draw deck upon playing/taking a card. I think that as soon as the card leaves the draw deck in such a manner, shuffling must take place.
So you play Ever My Heart Rises with Dunharrow Plateau. Do you...
1) Take it out of your deck along with the top six cards,
2) Play EMHR, shuffle your deck, and then take the top six cards, or...
3) Look at the top six cards and then decide whether to shuffle or not, hoping your opponent doesn't ask questions? 
I never actually thought about it, but I played as option 2. There is really not much difference between option 1 and 2 as long as you don't cross the line to option 3. Even with option 3, it's still a gamble, but with a little tip.