Also test all the tail and back-up lights and the wiring on the tow vehicle. Additionally, if there is rust or corrosion on the trailer frame it should be cleaned and repaired. Any damaged rollers or pads should be replaced or repaired also.
Extras
Extras are personal flotation devices, safety equipment and paper work. Remember; don’t leave home without it means more than the boat. Make sure you have a enough personal flotation devices for the rated number of the boat or at least for the number of people that you take with you.
You’ll want a safe and dry place to keep the registration and insurance paperwork.
You also want to make sure that all of your fire suppression and extinguishing systems are fully charged and in working order.
If there are inspections required, make sure they are done before you head out on the water.
One other thing to think about is having a good Marine First Aid kit.