Yup. You could do it all in one night.
However, there are variations of encounters, enemies and even several location variants every time and the character (1/2 of 5) you are playing will have a big impact on how you play the game.
Plus there are 4 levels of difficulty as well. Optional objectives in each scenario and so forth. It's not something one shot like TIME Stories.
Just got back from AK. If you run a solo campaign or one with 2 players, you could possibly finish a campaign run (3 sceneries) in as little as 6 or 7 hours (this is a bit padded due to time it takes to learn the game) plus maybe another hour total for leveling and deck building, but then you'd only see some of the story unfold and experience less then half of the characters (who all play out very differently). The bonus scenario we got at the event is a bit longer and tougher then what comes in the base box. You can also do campaign runs trying to optimize the starter decks OR try to do runs with your own customized decks.
There is a ton of content here (it may have fired Lord of the Rings and Warhammer Quest for me) and is only going to blow up in coming months.