Trains in Japan are quick, efficient, and (importantly) reliably timely. There are so many ways to get to Tanuki Lodge by train!
If you’re flying to New Chitose (Sapporo) Airport then you can catch the fast train into Sapporo and from there jump on a train to either Kutchan, Hirafu or Niseko. It is a very scenic trip and while slower than the bus, worth doing at least once. What you do from there depends on your other arrangements. Picking up your rental car in Hirafu? Then jump on the bus at Kutchan to get you there. Niseko Station or Hirafu Station might be good options if you have arranged for someone to come and pick you up.
If you are travelling on the train with your bike then you could ride from these stations in summer. Keep in mind Tanuki Lodge is uphill and you will be riding on highways.
Points to keep in mind: Waiting around a train station is a very different experience in an extreme winter than it is in summer. From Hirafu Station there is no way to get into Hirafu town unless you can talk someone into giving you a lift. Not always possible if you arrive late or in the middle of a storm and there is no one around.
If you have a phone that works in Japan and speak fluent Japanese you may be able to order a taxi but these stations can be cold spots to be waiting in sub zero temperatures.
Thinking of training it up from Honshu? If you flew into Tokyo or Osaka and have some time to spare there are several options for train trips. You can catch the Shinkansen to Aomori before changing over to the local Hokkaido train and travelling to either Niseko Station or Hirafu. Alternatively, you can replace the shinkansen portion of your trip with a slower train or even an overnight sleeper. Again, properly bagged it is possible to bring your bike on the train with you.
The trains travel all winter but keep in mind the possibilities of delays during extreme weather and avoid any plans that involve waiting around on stations in sub-zero temperatures. Not all stations have buildings you can shelter in and the temperature can very sub-zero! .