Hokkaido trip in Sep or Oct

We plan to go for 10 days trip to Shiretoko, Rausu, Daisetsu Park, Furano, Saroma Lake, Masshu Lake, Akan Lake in Sep or Oct.
(1) Can we camp? Open til Oct? Too cold to camp? Any website that we can see Camp information?
(2) Can we drive? Will Daisetsu snow in Oct?
(3) Is 10 days enough to cover these area?
(4) We like to see flowers, any flower in Sep and Oct?
(5) We like to see beautiful scenaries, any recommendation?
(6) We like to eat. Please advise us what are the seafood we can get in this season.
Many thanks in advance.

Can we camp? Open til Oct?

Opening periods vary with the camp ground. Try googeling for "Japan campgrounds" and similar. This is one of the results you get:
http://www.jnto.go.jp/eng/location/rtg/pdf/pg-804.pdf

Too cold to camp?

It is never too cold to camp if you bring appropriate equipment.

(2) Can we drive? Will Daisetsu snow in Oct?

In the higher mountains it starts snowing in late September, but in the lower areas (where most roads are), the snow does not usually start until late October or November. There are some higher located roads that may get snow earlier than that.

Is 10 days enough to cover these area?

Yes.

We like to see flowers, any flower in Sep and Oct?

There are some flowers left around Furano/Biei in September, but I think by October they start to get scarce:
http://www.furano.ne.jp/furabi/english/flower.htm
http://www.japan-guide.com/blog/schauwecker/110915.html

We like to see beautiful scenaries, any recommendation?

All the places you have listed offer beautiful sceneries.

Thank you very much for your kind reply.
Could you advise us which airport to touch down if we are coming from Tokyo?
Any website show youth hostel info?
Many thanks in advance.

Could you advise us which airport to touch down if we are coming from Tokyo?

I would enter through Memanbetsu and leave through Asahikawa or the other way around.

Any website show youth hostel info?

Here you go:
http://www.jyh.or.jp/english/

Thanks very much for your kind reply.
We want to aim for Asahidake's autumn in end Sep, Notoro Lake's red coral in Sep. Also want to see Autumn colors of other places such as Shiretoko, Rausu, lake masshu, Durango,....
So, just to double check, arrival airport still Memanbetsu? Departure airport still asahikawa?

Thanks in advance.