Tour packages usually take away the charm. You have two months prep time, enough time to still take advantage of good prices for flights and inns.
I've never used any tour package to go Japan. Me and my wife usually go over the destinations we'd like to go, places to stay/see, trains to take etc. Traveling through Japan is a pleasant experience in itself.
Don't worry too much about getting lost etc, as that's part of the fun too. The locals, even in big cities, are very helpful. The huge advantage mandarin speakers have is Chinese characters. They understand the classical Chinese characters, so when sign language fails, drawing the Chinese character for inn/train/toilet/shop etc works like a charm!
That said, if you're traveling with family, parents, children etc, a tour package becomes far more attractive as your kids will probably keep you busy enough! Either way, have fun in Hokkaido!!! :thumbsup: