As was said, probably not a ground invasion. But we are talking about Reagan here. This would have essentially given him a free hand (in US public opinion) against Cuba. So, maybe:
1) USN sweeps the small Cuban navy from the sea, literally sinking all of it, and bombarding those that are in port
2) airstrikes in Cuba to destroy the entire Cuban Air Force on the ground, and shooting down any that make it into the air
3) 100% blockade of Cuba, sea and air. Nothing gets in or out, nothing. Reagan announces that the blockade will end only when the Castro regime steps down.