Coin locker & bus at Yamanakako

hello everybody,
my family (and my big luggage) will go to lake Yamanaka for short day trip from Mishima station with express bus (reserved seat), and plan to go to Tokyo with bus express too from lake Yamanaka. and i wanna ask:
1. Coin Locker.
Is there any coin locker around lake, and where can i find it?.
2. Fujikyu sightseeing bus trough northern lake.
There is a sightseeing bus (Fujikyu bus) run from Kawaguchiko and go through along southern side lake bus stop and end up to estern lake, but i dont find any bus stop trough northern side lake (based on english timetable Fujikyu bus) is there any bus go trough northern side? because i want to go to Nagaike shinsui park. Or any local bus that go entire around on lake Yamanaka?
3.Big Luggage into Fujikyu sightseeing bus.
With that sightseeing bus, can i bring a big luggage into the bus? any extra fare? since i read the regulation about big luggage sholud to be put on trunk, and i believed there is no trunk on sightseeing bus.
4. Fujikyu sightseeing bus regular fare ticket.
About the fare, do you guys know about the fare between bus stop? because from the web, i only know about 2 days pass ticket for 1500 yen. since my trip is only a day short trip n not much place to go, i need to compare the regular ticket with a 2 days pass ticket.
Thank you in advance..

3. The bus looks like a Tokyo City Bus, you can think it is enough or not for big luggage.
4. Look at the map of the bus: http://bus-en.fujikyu.co.jp/pdf/heritagetour/routemap_retro_omni_20191... , at every bus stop there is a Yen symbol, it is the price that you have to pay from the kawaguchiko station.

@shalahuddinn, your link is not mention about Yamanaka Lake, it is same with Yamanaka Lake?