Man the mounted gun and shoot anything that comes through the entrance of the plantation. This is a rather simple matter – just make sure to take them all out before they get past your line of sight, because if the two henchmen die, it's mission over. That means take out the cars, then take out the drivers. After all the fun, head on up to the house, taking out the two guys that are attacking as you go.
After talking to the Sandman, rush outside and take cover and attack the next wave of attackers. Be warned: if the Sandman takes too much damage, you fail the mission. Take out the two cars that come down the road then a helicopter will land some men on the opposite building's roof, so take them out with your SAW. Next, a helicopter will come from behind and start attacking you. Make short work of it, either with the SAW or a bazooka type weapon, or with blind rage. Next, a wave of men will appear on the left from the trees, which can be annoying. Take them out quickly (blind rage is good here as well). Lastly, a Bodog Stampede will appear, so take out the drivers before they cause too much damage. Now talk to the Sandman.