Help with Stagazing in Achi, Nagano

It looks like there’s a few options to be found at http://info.sva.jp/, and we’re interested in the gondola night tour in particular (https://sva.jp/night_tour_2023/), but I’m struggling to see public transit options to/from “Heavens Sonohara”.

We’ll be doing the nearby Nakasendo Trail (Nagiso to Nakastugawa) the 20th or 21st of April and thought we could stay in the area overnight for this instead of the planned day-trip.

I see it’s only about half an hour to nearby Nakatsugawa by car, so can we assume we’ll need to use a taxi? Will this be hard to arrange at night?

Any stargazing even in Achi will probably do, but I’m at a bit of a loss.