Now tee time can be tune time!
Get the appropriate car stereo. You can use a regular receiver if mounted in a water proof area plus consider a unit with higher than standard wattage since you'll be combating outside noises. Don't go overboard on the cost though since golf carts are obviously exposed to the elements and not the type of vehicle that can be locked up. Add a decent set of outdoor speakers to your purchase. The speakers will be more exposed to the elements than the receiver so they need to be weather proof.
Mount the receiver. If the cart has a glove box you can mount it in there or cut a hole in the body under the seat. Anywhere that it is protected from the elements is good. The alternatives are to fashion a plastic cover on hinges or use a slide-out metal bracket so you can unplug the receiver and take it with you when not in use. Be certain that there is enough clearance behind the unit to run your wiring.
Mount the speakers. If your cart has a hard canopy, you can mount them underneath in the back corners, otherwise on top of the panel between the seats and the golf club storage area or possibly recessed in the kick panels. If mounting under the canopy, drill all the way through and use bolts, not screws. Also, apply silicone to the bolts on the top side to prevent leaking.
Get wired. Run the receiver's power lines to the battery terminals. Make sure red goes to a positive terminal and black goes to ground or a negative terminal. Next, run the speaker wire from the unit to the speakers. Always cut the wiring on the long side to make sure you have enough and keep the polarity consistent so that phasing does not occur. Consider soldering the wires to connect to the speakers since a cart rides a bit bouncy. You don't want to shake the wires loose. To make the installation appealing to the eye, you may want to drill holes in the shell to run the wires underneath and out of sight.
Grab your clubs and your cd's! A round of golf or even a trip to the mailbox can now be that much more entertaining. You're ready to not just roll but you're ready to rock and roll!