Somebody actually did the math on the episode, and it actually works RE: Travel. This was the first time I was bothered by "teleporting", as until know we could just assume a certain amount of time has passed off screen in that particular storyline. This is the one bit that a timeline.
That's great and all, but the episode makes it look like one day at most passes in between the time Gendry leaves and Dany shows up with her dragons.
Based on how dumb they were in terms of using the fire magic they had (Jorah's dumb "we're gonna freeze to death" line), they should have actually froze to death.
The show should have showed them acknowledging that they have fire magic to keep warm. Instead, we see Gendry leave during the daytime, then we see nighttime, then the next morning Thoros is dead, they light his body on fire, everybody walks away from the fire for some reason, then later that day Dany shows up.
Or they could have done the smart thing and had Bran, Melisandre, or one of the dragons contact Dany.