Do you count forced decisions made by either player? If so, it might be possible to get higher with attacks that have forced decisions: Rabble flips 2/3 treasures/actions, Rogue/Knight flips 2 cards, but only one is 3-6, Saboteur hits a 3 cost card w/ no Curses left. I'm not quite sure about Young Witch: in the vein of forced choice, you may reveal the Bane, but you can't, so you have to choose not to. But you could make the same argument for things like Moat and Watchtower: I could have revealed them, if I had them in my hand. Young Witch does specify the choice on the Attack card though, so I think that makes the difference.
Solution attempt:
KC/TR/BoM for 21 TR plays on stack, Rabble only action in hand.
9 times: TR Rabble, drawing 5 non-actions and Rabble, revealing all treasures/actions
TR Rabble, drawing 5 non-actions and Herald, revealing all treasures/actions
5 times: TR Herald, drawing a non-action and another Herald, revealing and playing 2 Saboteurs, hitting two Silvers with no Curses/Poor House in supply
3 times: TR Herald, drawing a non-action and another Herald, revealing and playing 2 Rogues, hitting only one 3-5 cost, and then forced to choose it to gain
TR Herald, drawing a non-action and Sir Destry, revealing and playing 2 Rogues, hitting only one 3-5 cost, and then forced to choose it to gain
TR Sir Destry, drawing 3 non-actions and Sir Martin, hitting only one 3-5 cost twice
TR Sir Martin, hitting only one 3-5 cost twice
21 TR choices + 20 Rabble choices + 10 Saboteur choices + 8 Rogue choices + 2 Sir Destry choices + 2 Sir Martin choices = 63 forced choices in a row. Probably can be improved to somehow include the other solutions without attacks, or used to improve them.