From Kyoto to Kawaguchiko

I have plan to leave Kyoto by taking private bus around 2pm. When should I get to Kawaguchiko lake? Is it too late for Onsen?
or Should I stay at Nagoya then visit Kawaguchiko next day?
Thanks in advance.

It is about 400 kilometers along the Meishin and Tomei Expressways. I would calculate at least five hours for the one way journey. So, without traffic jams and breaks, you could make it by around 8pm, which is early enough to check into your ryokan and have a bath. Depending on the ryokan, it might be too late for dinner, though.

Nagoya is only 100 kilometers into the journey.

Thanks a lot Uji. That's sound could be a long difficult journey! but our group hope it would be worth with fuji view in the morning.
About dinner, what time should I reach the lake in dinner time?

Further question, during in Kyoto(7.30am-1.00pm) is it convenient and to visit Kinkakuji, Kiyomisu and Fushimi inari by bus before leaving for Kawaguchiko lake?

Thank you for your kindly helpful suggestion.

About dinner, what time should I reach the lake in dinner time?

Most ryokan serve food between 6 and 8, but some should be able to serve after 8. Please inquire with your ryokan.

Further question, during in Kyoto(7.30am-1.00pm) is it convenient and to visit Kinkakuji, Kiyomisu and Fushimi inari by bus before leaving for Kawaguchiko lake?

Only if you know where to park a bus. Also, you will have to move at a fast pace and check opening hours.