Thanks this is a huge help. I'll be spending about 5 days in the Shari/Abashiri/Utoro area around February 1. There are some cruises offered from Rausu that potentially interest me, but the time investment to get there and back is probably too much.

edit: on closer inspection it appears that route 5 arrives rausudo at 10:45 not 11:45, cutting the travel time much closer to feasible. I might do it. Thanks again!