Can you reasonably enjoy Shiretoko if you are not a Japanese speaker? I only went as far as Abashiri (for the icebreaker drift ice tour) and didn't find it very gaijin-friendly. I think the only English speaking person there was at the reception of the Ryohyo museum.
Plus the public transport was quite limited and distances between attractions not pedestrian at all - I guess you need a car to enjoy it fully...