As everyone said already - you have a gorgeous gown. If I were you, I would give as much time as possible to take pictures with your dress either indoor or outside at the park.
Instead of using just flowers, have you thought of using decoration material from stores like Michaels (a decoration material big chain store at Bay Area, CA), and it can be given to guest as gift / favor at the ceremony too. Also, I think ilovebeef is right too - a BBQ at the park after rehersal is a great idea to save cost.