A few questions about the new arcane event pass

i havent played league much for about a year or two, and i didnt play much back the neither so idk how events like this work. 1. is the new caitlyn skin that you get with tokens only avalible durign the event or will it be purchasable in some way later on? 2. how hard is it to level up the event pass? Can i as a casual player get far enough for it to be worth buying?