HOTDQ SPOILERS AHEAD:
Just one brief update to this thread. Without going into too much detail, I would absolutely recommend letting PCs have some levels under their belts before starting HotDQ. It has worked very well through all three episodes my group has done so far. My group's fifth level PCs just wrangled the dungeon crawl of Episode 3 and found it surprisingly difficult: the bad guys there have amazing damage potential (even if you don't play the Roper at full power).
Two notes on this:
1) The rematch with Cyanwrath was a great encounter; the PCs absolutely hated him after their encounter with him in Episode 1 and unleashed everything they had on him. They did kill him without anyone dying, but the first round of combat (when they were more cautious) he nearly killed the Wizard with his breath weapon before they even knew he could do that! If I were to run the encounter with only third level PCs, I would probably try to find some way to communicate to them that half-dragons have breath weapons; they were expecting a melee-only combatant.
2) The Roper is definitely a tough encounter no matter how you slice it. By the book, between the kobolds and the drakes, the Roper fight is deadly even for a group of fifth level PCs. As a result, I made one minor adjustment to the encounter to make it survivable: I didn't allow the Roper to make critical hits. As it turned out, this was key to the balance of the encounter because the Roper rolled 3 natural twenties on bite attacks during the course of the battle. Any one of which would have instantly killed a PC (even the hardiest!) if it had been a critical hit. If I were to run the dungeon with only third level PCs, I'd probably remove the Roper entirely and just let the encounter stand with the kobolds and drakes.
