JR west or Kansai thru or reg ticket?

I never been to Japan using JR/ other train, my itenerary with 6 other people will be:
day 1: Arrive KIA osaka at 7 pm and straight to jhopper backpackers (kansai airport rapid service JPY 1160?)
day 2: osaka to comfort hotel nara, sightseeing to yoshinoyama area, todaiji temple and Horyuji temple (osaka - nara JRline regular pass JPY 780?) will we need any transport for sightseeing in nara?
day 3: nara-koya san and seight seeing koya san (JR + nankai koya line regular JPY 1390? )
day 4 : koya san - kyoto (nankai koya line+JR JPY 1740?)
day 5: kyoto the whole day and have JR pass 21 days start day 5 to day 25.

My question is for day 1 to day 4 should I buy kansai thru pass 2 days plus 2 days JR west kansailine or just buy regular ticket which total cost about JPY6000? Please please help me with this as we are 7 people in total and want to save some money and time. Thank you so much...

I think you underestimate the time it takes to get to and see Yoshinoyama. I think it is too packed to see Yoshinoyama, Todaiji and Horyuji all in one day. On the other hand, the additional trip to Yoshinoyama could justify the purchase of a 3-day Kansai Thru Pass to be used on day 2, 3 and 4. If you use one, make sure to use non-JR trains for all of your travel, including Kintetsu and Nankai via Osaka-Namba for access to Koyasan (this is faster anyway).

Thanks Uji,

We will split the sightseeing in nara at day 2 n day 3 before go to koya san? is it ok?

What about day 1 from KIX to JR fukushima station? buy regular pass?

Well now I become nervous about too pack itenary, would you please advise my next itenary:

day 4-5: Kyoto day 5 start using JR21daypass
day 6 : atami
day 7 : fuji hakone
day 8,9,10: tokyo
day 11: nagano
day 12: Matsumoto
day 13: Takayama
day 14: Kanazawa
day 15: kyoto again
day 16-17: Kotohira (want to see iya valley)
day 18 : arrive late matsuyama
day 19: take early ferry to beppu, stay aso
day 20: kagoshima
day 21-22: yakushima
day 23: arrive before 12 morning hiroshima (see miyajima, hiroshima jo, hiroshima monument continue day 24)
day 24 : late night arrive osaka
day 25: fly back home

Thanks alot and Regards,
Mei

Some parts are fast paced, but possible if you prepare yourself well in advance to ensure smooth moving.

day 6 : atami
day 7 : fuji hakone

When you write fuji, do you mean the Fuji Five Lake area? If yes, note that I don't recommend to visit both Hakone and the Fuji Five Lake in a single day, because there is too much transportation involved.

day 12: Matsumoto
day 13: Takayama
day 14: Kanazawa
day 15: kyoto again

These four days are rather packed, as you will be traveling 2+ hours on four consecutive days. Possible, but packed.

day 16-17: Kotohira (want to see iya valley)

The Iya Valley is tricky, especially if you plan to go there by public transportation. Make sure to prepare your visit well.

day 19: take early ferry to beppu, stay aso

Note that there is no more ferry from Matsuyama to Beppu (only in the opposite direction). You will have to travel via Yawatahama:
http://www.japan-guide.com/e/e2355_01.html#f39

day 21-22: yakushima

Yakushima is another place rather difficult to navigate by public transportation. I recommend to prepare it well. And just one overnight stay might be too short.

On the other hand, the additional trip to Yoshinoyama could justify the purchase of a 3-day Kansai Thru Pass

I just realized that the Kansai Thru Pass is not valid all the way to Yoshino. You would have to pay a supplement. But the pass might still pay off.

Dear Uji,

I don't know about fuji lake, what i mean is we gonna go to stay at fuji hakone guest house. is this the area you mentioned?

We will rent a car at kotohira to go to iya valley.
We also will rent a car at yakushima.

What do you mean by well prepared? for the days those you mentioned too tight?

Thank you

I don't know about fuji lake, what i mean is we gonna go to stay at fuji hakone guest house. is this the area you mentioned?

No. That is Hakone, a completely different area, many kilometers away from Mount Fuji. Here are access details:
http://www.japan-guide.com/e/e5206.html
http://hakone.syuriken.jp/hakone/

What do you mean by well prepared?

I meant that if you travel by public transportation, you should research bus lines and timetables in detail before going. However, since you go there by rental car, it should be no problem.

Dear Uji,

Can you help me where to buy air ticket from yakushima to kagoshima in advance, so we can get some discount for 7 people?
Thanks,
Mei

Here are some contact numbers for domestic flight reservations:
http://www.jal.co.jp/en/information/

Also, some of the discounts are available through the following website:
http://www.air-j.com/sp/japan-guide.com/

Thank you Uji,

May I ask something about transportation in Beppu? If we want to see the hells there, like : umi-jigoku (sea hell), the Chi-no-ike=jigoku (blood pond hell) and the Tatsumaki-jijoku (tornado), is there any public transport for that or should go by taxi?

It is explained on the following page:
http://www.japan-guide.com/e/e4702.html