Would like to check if it's easy to buy the Sagano Scenic Railway ticket in Kyoto if I get it maybe 5 to 6 days before the day of the ride? Just worried that it might be sold out

Klook is selling it at twice the price compared to if I were to purchase in Kyoto itself.
Also, if I'm going to USJ during the 4th week of May (probably on Wed or Thur), would I need an express pass? Not sure if the queues would still be long during midweek.