Exchange Rates

We have been coming to Zihua for years now ,and this season the property owner has changed the payment method to only pescos. My question is what bank or institution has the best USD to pescos rate in Zihua, and how's the safest way to get the currency to the property, without riding around in a taxi with a backpack full of money.
Not trying to be dumb gringo by asking stupid questions....but just asking.
Thanks, and hope this post doesn't devolve into a political discussion.