His promises won't be worth jack, quite frankly, given how extreme several of his past views and actions have been. I simply will never trust him to not succumb to the same gun-grabbing, pro-illegal and anti-First-Amendment inclinations he had as mayor. He will have FAR more power to enact such actions as president, and the temptations will therefore be that much greater.
I wouldn't trust any candidate. They will tell you whatever you want to hear. Look at their track record coming in to the election.
So your belief is that Rudy is running for President so that he can focus on social issues and leave a lasting legacy? I'm betting you couldn't be further off the mark.