Cobbling together a bare minimum of tickets with low-powered team was not in any capacity hard. I'd even venture out and say it would be possible to perfect the Lena (2 000 tickets for max skill and slots) without clearing most of event maps. Remember, the first maps offered ticket-to-stamina rates comparable to latter) Just, it would have been extremely time consuming.
Thankfully, autorun feature means you can just start the map and leave it alone in background)