Fuji shibazakura festival ticket and access

I m going to shibazakura fest. by car in the upcoming golden week and I couldn't buy ticket online from the site (always have error in the last page).
Q1 Can i buy the ticket at site of festival? Or i need to stop by Kawaguchiko to buy it.
Q2 in case traffic superjam should I wait or should I park the car at the station they recommend?
Thank you

1. Yes you can buy the ticket at the venue. Just expect it to be busy

2. Even you park 'at kawaguchi station' and take their shuttle it makes little difference as the Shibazakura festival is only accessed via 139 and the road will be busy ( so either stuck in your own car or stuck on a shuttle bus) :

*there is extremely limited car parking at Kawaguchi station - the festivals website is likely suggesting to those visiting by train 'to not rent a car but use the shuttle service' - if you are driving from Tokyo and/or driving to the area you'd best choose the Tuesday / Wednesday which maybe the least busy

** the best tip for traffic would be to stay in the area - then the next morning head to the festival and the traffic will be the 'least busy'. The afternoon is the worst time to go and the worst time to drive