I doubt that there is snow during Nov. in the places you mentioned. At most, maybe in Shirakawa-go, but even there it is doubtful. Consider yourself lucky if there is snow in Shirakawa-go because I have seen beautiful picture of the place in snow.The reason I bring up car rental is that the 4 places are close together and seem quite suitable for a compact road-trip, cheaper than public transport if there is a party of 4 or 5 travelling together. Gujo-Hachiman is comparatively harder to get to by public transport. By train it requires a train transfer plus a bus connection. By long distance bus, depending on which bus terminal (there are 2) you arrive, you may still need to take another city bus to get into town. Having said that, snow or no snow, it is wise not to take risk if you feel uncomfortable driving under unfamiliar road condition.
When we went to Shirakawa-go from Takayama during the month of Oct., we reserved our bus tickets the day before in Takayama. On the day of travel, there were less than 10 people onboard. If you really want to book your bus tickets in advance, try e-mailing the Takayama tourist info. centre at hidatio@hidanet.ne.jp. I think they can help with the Takayama to Shirakawa-go as well as Takayama to Matsumoto via Okihida parts. No harm asking them how they can help or point you in the right direction for the Gifu to Gujo-Hachiman part.
Good Luck
