Good travel itinerary

Hello,
I'm planning a trip for 4 people ( 3 adults and 1 teen) to Japan in March. I did quite a lot of research and came up with this itinerary:
(From 27 March to 6 april)

27th March: Arrival at Narita airport. Trip to Kyoto

27th-30th March: Kyoto

30th-31st March : Osaka (arrive early, depart late)

31st March to 1st April: Mt koya (temple lodging)

1st to 6th April: Tokyo

6th April: Departure

I'd like to know what do you think of my itinerary and if it's necessary to arrange the days in another way or id it's fine this way. I haven't booked any hotels yet.

Also: I'm planning on renting an apartment in Tokyo, since it's cheaper. How does that sound?

Thank you very much!

Why don't you just fly into Kansai instead of into Narita, then traveling down to Kyoto on the same day?

If you're flying into and out of Narita, then it's recommended to get the 7 day JR Pass, as it will pay off for your round trip to and from Tokyo.

If I am you,
27th-2th(First 7 days):
I purchase 7 days JR pass and visiting further place like a Kyoto, Osaka, Koya and Hiroshima, Nara etc..
3th-Finalday: Back to Tokyo and visiting any Tokyo spots then depatyre from Narita Airport.

I know some reference site if it help you.
http://www.japanrailpass.net/eng/en001.html
http://www.japan-guide.com/e/e2400.html
http://visitjapaninfo.weebly.com/

I can't fly to the Kansai airport because from my city that's 150€ more expensive..
I'm thinking of buying the 14 day Jr pass, so I can use it for as long as I want while I'm there, and avoid any problems

Yeah KIX fare from Australia are much dearer too, quite a shame.

As for your schedule looks good, you might struggle to find things to do over that last week in Tokyo though, but you can make day trips to Hakone/Kamakura/Nikko/Yamadera if you want. Personally I'd just spend 1-2 days max in Tokyo itself and put the other days to something else.

Does anybody ever answer "oh I hadn't thought ot that" when asked "why don't you fly into KIX"?

DO NOT get the 14 day pass. It is absolutely useless and a waste of money in the Tokyo area.
As already stated, the 7 day pass will pay off for your trip to Kansai and back.

Then if I buy the 7 day JR pass and activate once I get there,it will expire once I go back to Tokyo and I'll have to buy a NEX ticket to go to Narita right? Yeah I guess that'll be a really money saver. Thanks to all of you ^-^

Yeah, it's probably cheaper to buy a 7 day pass and activate on the 31st. See if you can find a cheap discount LCC flight to KIX from NRT, otherwise just get a 10,000~ yen airpass for one flight, cheaper than the Narita Express + Shinkansen to Kyoto.

Your itinerary is perfect, dont change a thing :) A 7 days JRP will be enough for going from Narita and back to Tokyo.

Get the Koya pass
Otherwise pretty sound plan
I prefer Koya to Hiroshima. But that's just me. Needed some nature and zen after city living.

Hey guys, just a quick update
Turns out I found a pretty good flight that arrivers at Haneda airport ( yey!).
Do you have any suggestions for going from haneda to Tokyo station?
If possible, using the JR pass would be nice..
Thanks!
:)

Just take the Tokyo Monorail from Haneda, it's covered by the pass.