Have a choice arriving in NRT at 14:30 or else 17:30 in July.
Departing again at 22:00. Will have 2 kids (5-7yrs).
Is it better to take the earlier flight and visit the temple and Omotesando street, or take the later flight and just go to the landside mall for a couple of hours.
From what I read, it will take 90mins to get to the temple from landing, which would have me there at 4pm. Is that too late in the day?
One thing you may want to consider is that Tokyo is hot and muggy as hell in July, even at 5-6pm. I usually do better in heat and am not particularly prone to sweating. But even then, I find it difficult to bear being outside in Tokyo for even a short while.
So you've got some things to consider, esp when you have kids. Will your kids be tired (ie, what time zone are you coming from)? Do they do okay in heat? Do you plan to shower before the connecting flight (either via lounge access or at NRT's shower facility), or are you okay to fly in your sweaty sticky clothes?
Knowing how oppressive the heat is, I'd personally either just stay in the airport or take a cab to the nearby Aeon mall and hang out there. But don't let me talk you out of it, if you really have a burning desire to go check out Narita and the temple.
One other thing... if your transit occurs 7-9th July, then they're having matsuri (festival) in Narita city. The whole area from around JR Narita Sta up through Omotesando to the temple is matsuri area. I think that would be a neat opportunity for you to see what a typical Japanese matsuri is all about. So if your date matches, then I would try to go see that, the heat notwithstanding.