It would have been much more difficult for them to have found Drogon’s lair, since there wouldn’t have been any tracks between Mereen and there. (Maybe they asked witnesses along the way to see which way he had been flying.) Once they found that, Danaerys couldn’t have gone very far from it. Even if she had been hard to track in the grass, the tracks of Dothraki horde would be easy to see, even from a distance. And once they found the spot where she had been surrounded it’s not implausible that they would have looked around at the spot where she likely would have been standing. (Of course, this doesn’t explain why Drogon left his lair when Dani couldn’t get him to do it earlier.)
Ran out of goats?
I can appreciate that, thanks. It’s more plausible than Areo being killed by a lawn dart to the scapula, at least.
Might want to check down at the peanut-butter factory: https://www.youtube.com/watch?v=6VvLSyQ7eOQ
Maybe. It’s unclear exactly how much time has taken place between Dani’s capture and Jorah and Daerio’s finding the lair. It’s evidently at least a few days.
But that doesn’t explain why, if he can now fly again, he doesn’t go in search of Dani. A Dothraki horde can’t be hard to track. Even aside from the hoofprints, you can probably smell it a hundred miles away.
And if he’s hungry, some nice juicy horses are going to be more tempting than tough goats.
…and immediately sign with the New York Knicks. 
Drogon’s motivations are unclear. Clearly he doesn’t just hang around Dany all the time. And maybe the fact that he got stuck with a lot of spears last time he tried to come to her rescue makes him less likely to do so going forward.
Maybe he can sense when she’s in danger. She’s not currently in danger. If I were Drogon, I think I might prefer Dani living out the rest of her days in the widow camp instead of all this leader stuff where large mobs with spears occasionally try to kill her.
Sansa is presumably going to get to Castle Black, She’s the rightful lord of the north and is going to need a senior adviser to regain the north. Even if John Snow is resurrected, released from his vows by death and made legitimate by Sansa I just can’t see him taking up the mantle of Lord of the North in Winterfell.
His role seems to be much more focused on stopping the white walkers. I can see Sansa leading an army of wildlings south to regain Winterfell at some point, promising them lands for getting Winterfell back.
I think the next episode will start with Jon immediately dying again, because he still has all those stab wounds.