- Since this long route crosses one of the largest of the main Japanese islands, you have many options at each stage of the journey. Many of them have already been covered on the North Hokkaido Alternatives page, so be sure to check this page as well.
Another promising option would be to head west instead of east from Sounkyo and see Furano and Biei which have some very popular scenery (the flowers of Furano are a must for any Japanese tourist traveling in Hokkaido in July). You could then either go west and switch to the North Hokkaido route, going up the coast to the Saronbetsu-genya, one of Japan's finest wetlands (shown here) and north to Wakkanai and the twin islands of Rebun-to and Risshiri-to, or you could go southwest back to Sapporo. Or you could view Biei/Furano as a detour and simply continue on with this route by heading north and then east to Shiretoko. Or you could just save some of this for another trip - Hokkaido is so big that you can only see so much in a single journey.
If you've gotten all the way to Nemuro, you might want to visit the islands offshore... but, alas, wanting is about as far as you'll get. These are the disputed Kuril Islands, Japan's "Northern Territories," currently claimed by both Japan and Russia, and it's difficult for even Japanese to go there to visit their ancestors' graves. If you simply must set foot on Russian soil, a ferry from Wakanai to Sakhalin is a much more realistic goal. You can also go to other parts of Russia (such as Vladivostok), but only from Honshu, not Hokkaido. In either case, you'll need to get a visa, and in advance. Check out the Alternatives section of the North Hokkaido tour for a little information on getting Russian visas, and of course be sure to double-check the info by contacting the Russian consulate.