I just got off the phone with La Paz County Park. Yes, they will have the lagoon ramp closed down for a blues festival, but there's another ramp at the park we can use.
Its only $5 to launch and $4/person to use the park. There's amenities like bathrooms, picnic tables, etc...
Pictured below is the following:
Red: The lagoon ramp thats closed
Yellow: The ramp we can use
Blue: The beach area we can use

La Paz County Park is about 8 miles north of the Bluewater. It is located just south (right next to) the RoadRunner floating bar and grill.

Any constructive input is more than appreciated. I am doing my best to accommodate everyone with the conditions of this trip we were given. I am sad to find out that the fact the beach/river is closed in front of the Bluewater due to the drag races has been a deal breaker for some people to attend this trip. I understand and I apologize, I will try to make this more convenient for everyone next year.