How to get to Hokkaido?

Can I know which is the best or cheapest method to get to Hokkaido ard 30 Sept from Tokyo?

Is there other method beside travelling by night train and air?

Hokkaido is a large island, and access details depend on where on Hokkaido you intend to go. I assume you want to go to Sapporo. Here are your access options:
http://www.japan-guide.com/e/e5306.html

Thks Uji for the information.

1) Can I use the JR East pass to go to Sappora using the following way:

Take JR Tohoku Shinkansen to Hachinohe train (3 hours). Then, take the JR Hakucho limited express to Hakodate (3 hours) finally the JR Hokuto limited express to Sapporo (3.5 hours).

If not what pass do I need to buy in order to take the above route.

2) If I want to buy either the Hokkaido & Higashinihon Pass or JR Seishun 18 Kippu pass. Where can I find the timetable for the local trains so I can plan the timing for my trips. If not can I know the last timing for local trains service.

3) For either the JR Japan Rail pass or JR East pass can it be used on the Narita Express?

Greatly appreciate if anybody can help with the queries. Thank you.

1) Can I use the JR East pass to go to Sappora using the following way:

Take JR Tohoku Shinkansen to Hachinohe train (3 hours). Then, take the JR Hakucho limited express to Hakodate (3 hours) finally the JR Hokuto limited express to Sapporo (3.5 hours).

No! The JR East Pass is only valid as far as the northern tip of Honshu Island (that is somewhere between Aomori and Hakodate). It is not valid in the tunnel between Honshu and Hokkaido, and it is not valid on Hokkaido.

If not what pass do I need to buy in order to take the above route.

If you hold a JR East Pass, you would have to pay for the fare and express supplement for the section that is not covered by the JR East Pass (which costs about 12,000 Yen).

About the JR East Pass:
http://www.japan-guide.com/e/e2361_02.html

Your options for accessing Sapporo:
http://www.japan-guide.com/e/e5306.html

If I want to buy either the Hokkaido & Higashinihon Pass or JR Seishun 18 Kippu pass. Where can I find the timetable for the local trains so I can plan the timing for my trips. If not can I know the last timing for local trains service.

You can look them up here:
http://grace.hyperdia.com/cgi-english/hyperWeb.cgi

And the following sample timetables might not be 100% up-to-date, but they give you an idea:
http://www.japan-guide.com/e/e2362_03.html

For either the JR Japan Rail pass or JR East pass can it be used on the Narita Express?

Yes. Both passes can be used on the Narita Express.

PS: Please post eventual subsequent questions to this thread rather than creating a new thread.