Getting to snowfes from Niseko

Hey. Going to be in Niseko as a seasonal worker over winter. Wondering how easy it is to get to Sapporo to see the snow festival. Can it be done in a day by taking the last train at night?
I’d stay the night if there was any accom left (I know it’s already booking up now), and if I had two days off in a row but that may not be possible.