Planning 18th-28th Oct! going up north to Daisetsu first and down south to Hakodate after that! hope i still can catch a glimpse of the Autumn!

Japan always do advance thing in 3 month gap only. From Hotel to Transport , to any ticket reservation.
Now only July ...3 month gap , means until Sept only.
You want October timetable have to wait until August

Hotel inside Chitose Airport are only choice.  Expensive but similar if you taking Taxi to Airport (early morning rate) also cost the same.
Hotel Info:
http://www.air-terminal-hotel.jp/eng/
First do you really need the JR Rail Pass or not? I want to know your plan first.
Buy from JTB Malaysia are most reliable
Bro, Today just 1st of August only. Where got so fast. Minimum 8 August 16 la .
Japanese also human not robot. They need time plan the 3 months schedule also.  Minimum give them 1 week.

Minimum RM6000 above because including accommodation
Rm 10000 above if you want to try King Crab meal

Hokkaido have too much delicious seafood but comes with expensive price tag.  Everytime I go inside Hokkaido seafood market, sure spent Rm1000 - 1500

October are starting into autumn season.  If you got at Late October, it will be high season. Most expensive season.

Give you my sample Hokkaido (Autumn/October) itinerary to get an idea of how many days in each section, etc: http://look-see-eat.blogspot.sg/2015/11/ho...rket-ramen.html

If you are foodie, go Hakodate and eat this uni don, freaking delicious.

i'm using this
https://www.japan-rail-pass.com/
put it 10k, due to RM is weakening
Onsen hotel/ryoken is very depending, price can be huge different
standard 3 star hotel will be RM300~500
room rate for 8k yen to 15k yen conside cheap in japan
so far the highest i stay was 60k+ per night, and this is consider middle top only.

Yes. There are luggage storage at Gotemba Station.
Best way was used "Black Cat" Service once you check out from Shinjuku Hotel. Ask them sent to your next Kawaguchi Hotel.
http://www.japan-guide.com/e/e2278.html
It will save you alot of time, because you no need waste time go back to Station reclaim your bag.
Mid of October are Hokkaido best timing for autumn view. It also Hokkaido most expensive time.
Seafood at Hokkaido also high season from Sept - Jan. 

1st class King Crab price are most expensive at this period.
2nd Class Ekizen Crab price are higher than normal due to high tourist season.
3rd class Hairy Crab will be cheap because high season...alot of catch.

ur trip itinerary is almost similar to mine except for jozankei
it would be a solo trip for me n im i'll be taking train as usual

day 1 sapporo
day 2 biei
day 3 furano
day 4 kurodake
day 5 otaru
day 6 -7 sapporo

im buying this pass for JPY6,500 > http://www2.jrhokkaido.co.jp/global/english/travel/
this will cover furano, biei and ashikawa

for otoru, i buy this pass for JPY1,700> http://www2.jrhokkaido.co.jp/global/englis...ss/welcome.html

but for sounkyo no choice, hv to buy separate. to/fro asahikawa to sounkyo via kamikawa is about JPY4,000

seems ok, but rmbr 6.5k is for 4days

yeah, since u in group better rent a car.
can cover more area.

almost same like mine.

day 1 Asahikawa
day 2 Wakkanai
day 3 Abashiri/ bihoro, lake tofutsu, shiretoko
day 4 shiretoko
day 5 sounkyo
day 6 sounkyo
day 7 biei, shikotsu lake, otaru
day 8 cape kamui, kutchan, sapporo
day 9 sapporo
day 10 airport

cost rent car for 8 days is around 45k won from tocoo. honda fit/jazz and free pocket wifi.

i just booked thru the website.
pickup on 11th nov and return 18 nov.
under honda rent a car sapporo.
car: honda fit (jazz)
free internet and hokkaido expressway pass plan
total rental payment is 45,144 yen

its free pocket wifi. both car and pocket wifi collect at airport.
just free hokkaido express pass plan. if u want etc card u need to pay more
we plan to use routes without tol.
that is the cheapest rate i compared among all. straight away i booked.

i booked it last June. the price all include car, insurance, pocket wifi and HEP. 45,144 yen. roughly around 1.8k for 8 days.

i booked it last June. the price all include car, insurance, pocket wifi and HEP. 45,144 yen. roughly around 1.8k for 8 days.

i also booked Honda Fit. but not include ETC.

dai ichi takimotokan have 3 type of room
2 Pax , 5 Pax , 8 Pax Room

Those City hotel can go cheap choice but when comes to Onsen Hotel must go luxury.