You will Miss it. If late Oct at Hokkaido.
You want to catch Hokkaido best Autumn, Have to go at Mid October.

yup mid of oct is best bet, but i will choose mid to end to be safe
from my experiences, the tree turn yellow+red is varied by locations
mountain area, forest and city... all hv their own timing
so dont get ur hope too high, as there is no perfect timing

if u planned to drive, u hv more chances to encounter yellowred hill/gorge/highway/bridge/dam

i went on first & second week, i recall only 40% or less is converted
i guessed mayb global warming delaying the winter 

deodorant, mayb can gv more accurate answer, i think he went at the end of oct

I been there 1st on oct 10 till 14 n 2nd time 2 year after on oct 25 till 28. All I can said it really depend on luck, area n timing. But I think the third week of the month is the best. I am talking bout sapporo here. Northern hokkaido may be early. Southern mayb later. My 1st trip there only mountain area turn red n yellow. My friend said a bit early. My 2nd trip there macam a bit late pulak bcox it is red n yellow but is dying soon plus it snowing on oct.... lol... seldom snow on oct 1. Tat y I said it depend on luck. Haha....

first thing first
1. read the thread... or page #1
2. no need etc, pay cash
3. noboribetsu -> lake toya

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 think you should get the insurance.
Coz at least it would cover up in case anything happens.
I m not saying Japan is dangerous or what!? Insurances coverage always "just in case".

I saw some fb posted RM13/day for pocket wifi. Unlimited plan. By Travel Recommends.

jus take the insurance
Japanese is very nasty if u accidentally knock them

my father's frenz accidently knock a japs bumber here (minor accident)
he then goto hospital to do full body medical checkup, physiological evaluation and charge it to him, means lawsuit with other small compensation

very nasty stuff