Shinjuku to Lake Kawaguchi assistance

Hello,

I am trying to book travel for myself and 6 others (7 total), to day trip from Tokyo to Lake Kawaguchi on Tuesday Oct 21st.

I have looked at a number of websites and am getting overly lost and confused by the options and scenarios, and was wondering what people would recommend? Specific companies/sites would be super helpful!!

Our preference would be train but that is not a strong opinion.

Thank you for any help!

by lamontagne04