If you are confident in returning over the coming years, then why is the itinerary so rushed and cramming in so much stuff? I would stick to Greater Tokyo and do a few day trips if you desire (but there's so much to do in Tokyo itself in what sounds like your first trip) for the first half and then move onto Kansai for the second half to knock off Kyoto and maybe a day in Osaka (but Nara is probably a better bet).

You also state in a later reply that Hiroshima & Miyajima is a must do so perhaps the first half of the trip can be spent in Tokyo (and a day trip if you desire) and then I'd fly to Hiroshima to save time and spend the two days/one night at Hiroshima and Miyajima. You can then hit Kobe on the way back as the start of a long day before your ten pm flight out of KIX. In this case, Kyoto and Nara will have to wait till your next trip.

As txflyer77 indicates, using a Narita hotel as your base to explore Kamakura or Mount Fuji is not what you want to be doing. It'd be like staying by Dulles Airport to go visit Baltimore.