There's no way to sync a Marketo Smart Campaign to Salesforce. The only option is to sync a Marketo Program to a Salesforce Campaign and even then it would be the Member Statuses that will be synced over. Some users have the statuses of the Program listed as Open, Click, Unsubscribe, etc but the thing to keep in mind is that each Lead can only be in one Program Status at a time so if you did a little math using the Program Statuses you could extrapolate the numbers. ie is a Lead has Clicked status then they must have Opened the email too.