Hokkaido Itinerary with Rusutsu

Hello,

I would appreciate if you could give me feedback and ideas on the following 6 night itinerary in Hokkaido coming up in late January/early February:

1. Rusutsu skiing (3 nights) - flying into New Chitose and will take the bus over to the Rusutsu resort. We have an epic pass which covers this resort which is why we’re going here vs others
2. Other areas nearby (3 nights) - Not sure whether to rent a car or take transit. We’d like to stay at Onsen resorts and see the lakes, or do Otaru, Sapporo but prefer less crowds. Want to make the most of the three days.

We have flexibility to depart from Hakodate or make our way back to New Chitose depending on where we go beforehand. Also flexible and could do skiing the last 3 nights.

Additionally, could you let me know if it's feasible to rent a car in Rusutsu and be able to drop it off in Hakodate 3 days later? Is there any concern with driving in the weather during this time?

Thanks!