Travel options for birding in Eastern Hokkaido mid-March

Transport options for birding in March in Eastern Hokkaido

I'm planning to go to Hokkaido next March and want to spend 9-13 March to go birding in Eastern Hokkaido. This means that I want to get around the crane observatories in Kushiro and drive to Rausu for a drift ice excursion.

Now I see two options to undertake this:

- Book a guided tour for the crane observatories; travel to and from Rausu by bus (however I havent been able to 100% confirm that the bus is available and in Rausu hike towards the Fish Owl observatory.

This option is more comfortable but less convenient; especially since a 30 minute walk is needed to reach the Fish Owl Observatory from Rausu. 30 minutes would normally not be that much of a problem to me, but of course I havent experienced Hokkaido in March.

- Book a rented car. Visit the crane observatories by car and perhaps choose an additional interesting location or two to visit (I have a few in mind). Then drive to the Fish Owl Observatory by car.

This option gives more freedom but might be less comfortable depending on the weather. I have a bit of experience in winter driving, but this would only be my second time.

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Are either of these options feasible, and if yes, what would be the smartest choice to make. I know that of course a blizzard could ruin both plans; but what I read from other posts that will always be a coin toss in March. Reading up on weather predictions beforehand will hopefully make me decide beforehand whether its smart to go down to Kushiro.