Japan Rail Pass and Lake Kawaguchiko

Hi

I'm currently at Ikebukuro, and having missed the Cherry Blossom season in most of the cities in my trip, I found in this webpage that the Sakura are on bloom at Oshino Hakkai, 25 min away from Lake Kawaguchiko.

I've done a bit of research and I'm really confused on how to use the Japan Rail Pass to get to Lake Kawaguchiko. Some webpages mention I can use it, others that I can't, some other that I need to pass a full fare of 2460 from Shinjuku and others to travel to Otsuki and pay 1140.

What are the cheapest and faster options we have? With and without Japan Rail Pass. Timewise suggestions would be appreciated as well.

Is tomorrow still a good day to go see Cherry Blossoms and Fuji-san at Lake Kawaguchiko?

Thanks in advance

Already tommorrow, are you still in Ikebukuro?
Unfortunately,your post shown about 50 min ago, too late isn't it?
https://i.imgur.com/88QH2Ap.png

Japan Rail Pass covered until Otsuki fr Ikebukuro,
so you must pay later section FujiQ railway(not JR) fee.

Well, if it's not too late, ride the Yamanote to Shinjuku and you can catch a bus to Kawaguchiko for about 1700 yen each way. There's no way to get there for free on the train with your pass, and it takes longer than the bus anyway.

On JRP you pay a "supplement" for the non-JR line. It's a bit over 1000 yen (US10) so not going to break the bak.
Did you consider some of the futher afield options? I plan on covering Kakunodatte from Sendai/Miyagi later this week because Odawara will problably be finished by the (it was great last week).