You should have no problem.
Our boys often split meals, and we usually eat one sit down a day. Our boys prefer breakfast in the room, so we bring stuff from home, pop-tarts, cereal, etc.
We snack all day long, so we dont spend a fortune every day on a nice sit down meal.
Our last two trips we averaged $65-100/day for food, extras and souveniers. And we bought our boys way too much stuff.
If this is your children's first trip, enjoy it through their eyes, it will open yours in ways you never imagined.
Also, we find by letting our boys dictate certain things we do, they feel more in control and have very few "meltdowns".
Finally, HAVE A GREAT TRIP!