sawada park open air hot spring

End of December, We are travelling to Hakone for a one night stay at ''Hakone Dougashima Onsen Taiseikan Hanakajika'' near Miyanoshita. We would love to visit Sawada Park open air hot spring the day after we check out of Hakone for a dip before heading back to Tokyo by the same night (We have accomodation booked already). The transport to West Izu is very confusing. We have to take public transport to get to Sawada Park from Miyanoshita. Could someone give us some idea? Has anyone been to sawada park open air hot spring in winter? Is it worth all the travelling? Will it be very long and difficult to get there?

I hope you do not confuse Dogashima in Hakone (where you stay overnight) with Dogashima on the Izu Peninsula (where Sawada Open Air Hot Spring is located). The two Dogashima are a long bus journey apart from each other:

1) From Hakone, take the bus or train to Odawara (1 hour)
2) Take a train from Odawara to Mishima (45 minutes)
3) Take a train from Mishima to Shuzenji (35 minutes)
4) Take a bus to Dogashima (90 minutes)

Thank you Uji for clearing things up. No wonder it takes hours to get there, I didn't realise they are completely different "Dogashima"s. We'll have to plan for Sawada Open Air Hot Spring another time then.