Hokkaido help. Train?Drive?

Hi guys,

Will be going to Hokkaido in Mid May with a group of 4. It will be our first time visiting Hokkaido, Sorta in a midst of planning and so far only confirmed going to Sapporo & Asahikawa.

Got a few questions that i need help with and hopefully will receive some replies

Is Furano / Biei flower gardens open and worth going in mid may?

Any recommended Hotspring resort to stay in?

Is Lake Toya worth going to?

& lastly, if we were going to all these places is it more worth to drive or to take trains?

Thanks for any replies!:s12: