I recommend a portable radio. A car stereo is designed for an in vehicle experience so if you plan on sitting outside your vehicle it will be very muted (my SUV has Bose stereo and it was still very quiet). The neighboring cars will not help at all with audio volume. Tldr Inside vehicle- stereo will do just fine. Anything outside of the vehicle- bring a portable.
They have 2 separate radio stations, one for each screen. You can bring a radio but I usually just use the car. You can't leave the engine running but you can start it up between movies. They also have golf carts with jumper units that drive around jumping any vehicle that won't start.
So they have a station you will need to tune in. It is up to you if you'd like to use the car radio or take a radio.
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