So can I recommend this route? Well... conditionally. For one thing, this photo shows a lot of what it's like: tunnel after tunnel, with not a great deal of space for cyclists. More to the point, the scenery is strikingly like the more truck-infested portions of the Japan Sea on Honshu... and if you want that kind of scenery, you should probably not spend the time and effort to get all the way to Hokkaido. So you might want to consider going inland, at least as far as Mashike, rather than taking this road. What does make this stretch of road special is that it’s practically brand-new: up until around a decade ago, travelers were forced to take a ferry to cover this interval. So some people come here specifically to travel this route by bus.

My day's journey ended at Mashike, a few km before Rumoi. Unlike my harsh words about the road here, I have nothing but good to say about Mashike: sort of like a rural Otaru, with lots of old buildings from nearly a century ago - including this elementary school (you're looking at the gymnasium), a collection of huge wooden buildings that somehow have survived for 66 years without being destroyed by fire. The owner of the friendly Toho-yado I stayed at taught all of the guests how to open and extract the meat of a sea urchin (not so easy), and the proper way to eat amaebi (tiny shrimp - I think the official name is deep-water shrimp).