neuron

As most hotels typically do not allow check-in until the afternoon, I would suggest contacting the hotel to see if they have the capacity to allow an earlier check-in (even if it will cost you a fee). That way you can play it by ear as the state of the family's energy level.

I find a shower helps to revive me after a TATL flight. If the kids are still tired, they may need a small nap (2hrs, no more to keep them going for the day) and hit the streets for an afternoon walking tour (or drop by the discount theater ticket sites and snatch a cheap seat.)