Rusutsu to Hakodate

Hi,
Can anyone kindly advise me on how to go from Rusutsu Resrot to Hakodate?

I googled many answers like taking the Donan bus to Kutchan Station before transferring to JR Oshamambe station where it will lead to JR Hakodate station.

There are other answers like going straight to Toya or Otaru JR station.

Please kindly advise.

Thanks!

JR→バス（Kucyan)大変！1日に６本しかない。

簡単なのはJRで函館→札幌。
札幌から無料専用バスに乗ること。