I took a bus from Shibuya Mark City to Lake Kawaguchiko. It was easy and the reservation is free. If you’re late, you can get on the next bus for free. If you booked RT tickets and want to leave earlier than scheduled, you can have it changed for free as well! There’s ample leg space and no transfer, much better than taking the train not to mention it is the cheaper option.

AloJapan.com