I just thought that making it a Duration would be better because then you can keep track of how many have activated. As Davio said, it's hard to keep track if you have multiple choices to make.
Making it Duration wouldn't help, since it gets trashed anyway. You could reword it to work like this, I suppose:
GAZETTE, $2, Action, Reaction, Duration
When you gain this card, set it aside.
~~~~~~~~~~
When a player gains a Province, put this card into play.
At the start of your next turn, Trash this. If you do, choose one: +2 Cards; +2 Actions; +2 Buys; +$2; or trash two cards
That would function as a more normal duration, since it needs to be "in play" to actually do anything. But I think the reaction-only version is simpler. I don't think you need to worry about keeping track. You can already Procession a Pawn, or even Processioning anything requires you to track how many of what you have played, even without them being in front of you.