My Itinery re: timing and JR pass

I land in osaka on 02/06/08 then im meeting a mate who lives perm in Sapporo. The plan atm is to spend one week seeing Osaka, kyoto then Tokyo before travel to sapporo. I am thinking of buying a JR pass for those seven/eitht days and finishing it on the overnight train from tokyo to sapporo (through the under sea tunnel, i forget its name).

I will spend almost 3-4 weeks in sapporo (hokkeido sounds really nice up there at that time of the year) and catch a flight back down to osaka on 03/07 before i return home on 04/07.

I know that it would be nice to see more/other parts of central and southern Japan, but thats my plan atm.

Any suggestions on things i REALLY shouldnt miss out on (eg: change my plan cause the tourist attraction/thing is just way too good to miss), or considerations regarding if i should use the 7 day JR pass?

The two night trains Tokyo(Ueno) to Sapporo are not for free for JR Rail Pass holders.
The train Tokyo(Ueno) to Aomori is free for JR Rail Pass, but then you need an extra JR Rail Pass day for daytime travel Aomori - Sapporo. What you can do with JR Rail Pass is a 10 hour daytime travel Tokyo shinkansen Hachinohe ltd express Hakodate ltd express Sapporo, starting before 07.00 h arriving 17.00 h.

ok, thank you, i thought i had read somewhere in the Lonely Planet that the over night train was included in the JR pass (but maybe had to pay a little more for a "sleeper" option. Am i wrong?

if i am, then the day time option seems fine. so is it just 2 separate train trips and do they still go through the tunnel?

For your options on night trains with JR Rail Pass ( plus additional payment or free ) see under travel - Transportation - Night trains in this japan-guide.

There is a supplement to pay for a couchette when using a JR Rail Pass, 12,000 Yen, on the cheaper of the two night trains from Ueno to Sapporo.

It is three separate trains. Shinkansen Hayate from Tokyo to Hachinohe, Limited Express Hakucho or Super Hakucho from Hachinohe to Hakodate and the the Limited Express Hokuto or Super Hokuto from Hakodate to Sapporo. Here are the three best options:

Tokyo 06:56 - Sapporo 16:58 (10hours 02min)
Tokyo 07:36 - Sapporo 17:29 (9hours 53min)
Tokyo 08:56 - Sapporo 18:59 (10hours 03min)

The Hayate shinkansen is reserved seating only and can sell out a day or two ahead, I would suggest you make your reservation for this and the other trains as soon as possible.

All trains between Honshu and Hokkaido go thru the tunnel.

I'd show at first daytime train connections from Tokyo to Sapporo.

Tokyo--(Shinkansen Hayate)--Hachinohe--(limited express Hakucho)--Hakodate--(limited express Hokuto)--Sapporo

6:56hrs - 10:03/10:15 - 13:14/13:29 - 16:58

7:36 - 10:39/10:50 - 13:58/14:13 - 17:29

8:56 - 12:03/12:16 - 15:12/15:23 - 18:59

10:56 - 14:03/14:15 - 17:33/17:55 - 21:31

12:56 - 16:03/16:14 - 19:20/19:42 - 22:56

There is one more connection which involves an overnight train ride.

Tokyo 17:56--Hayate--20:59 Hachinohe 21:18--limited express Tsugaru--22:18 Aomori 22:42--express Hamanasu--6:07(+1) Sapporo

On this particular connection, you can utilize the last day rule of the JR pass by taking the overnight Hamanasu train.

On this train, 'Nobinobi carpet car', or the carpeted semi compartment is free for a JR pass holders.
http://homepage1.nifty.com/hodo/burutore/hamanasu/img/hama_2...

Happy travels.