Listed below are a number of teaser ideas based upon historical events.
Town assaults are a feature of piracy more akin to the 15 and 1600's rather than the 1700's. They were based more upon ethnic lines - ie English assaults, French assaults or Dutch assaults, and usually involved fair numbers of men and equipment. Ship numbers could vary from 2 upto a fleet, with numbers of men in the several thousands. Smaller assaults could take place with the number involved being less than 100 per side. While we imagine town assaults were all against the Spanish, this was not always the case, though rarer. The Spanish also counter attacked English, French, Dutch, cimaroon, indian and pirate settlements.
Quite a number of town assaults featured trickery and turncoats. Quite a number of ex citizens, slaves or prisoners would often inform another nation of the weaknesses of a town so that it could be taken, usually with a share of the takings in mind as a reward. Pirates also questioned nearby citizens what defences the town had, and may also find weaknesses out that way. Converesely, the citizens may also lie about the strength of the defence so that the pirates may move on to easier pickings. Cimaroons were also of great use, particularly in the Panama area attacks. Cimaroons were so bold as to attack Spanish towns on their own.
Most noteable towns were protected by forts on headlands or strategic hills, and sturdy stone walls on the landward side. Some such as Cartagena had several fortrs to get past. Forts could range from small wooden palisades and earth banks upto so called Spanish Castellas - a Caribbean version of a rennaissance star fort/medieval castle, with defensive walls so grand direct assault would be pointless. These also give the opportunity for siege assaults, some of which lasted upto 8 days.
Town defenders in the 1500's also included numbers of native indians, and even some negros. They could also be made up of armed civilians, visiting sailors and anybody else that could be scrounged up. Some larger Spanish towns were also able to field numbers of cavalry.
Ship assaults fairly speak for themselves. Bear in mind alot of pirate vs merchant combat was short and decisive, with just a few gun shots needed for a merchant to strike colours. Combat rarely ever lasted long enough to go below decks, though some pirates did prefer to blow themselves up rather than surrender - such as Blackbeard. Attacks on Spanish galleons, particularly the larger ones, could last for days on end with no result.
In the earlier periods, there was considerable fleet vs fleet action, with the use of fire ships, canoes, pinnaces and rafts to beef up numbers. Ships were also used to help defend ports against assault.
Fighting merchants ships, and even pirates in the later era, could see very small crews in operation. Some merchants vessels could be down to a handful of men, and for example when Calico Jack was captured, he had a crew of only a dozen pirates.
One other avenue of combat is that several pirate tales tell of assaults on ships by pirates in canoes/piraguas rather than sailing ships.
The Spanish Treasure Fleet escaped all attempts by Caribbean pirates. The worst they had to contend with was when a single ship was isolated from the fleet.
One alternative is when the Treasure Fleet was sunk and a salvage attempt was made. The salvage base was attacked by pirates who made off with the booty.
Attempts were made to intercept the silver mule trains from Panama to Nombre Dios/Portobello. These trains were composed of a long line of mules, upto 100 or so in number, under the escort of Spanish soldiers.
Pirates attacked small settlements for a number of reasons - the pearl fishing haciendas of Margarita, isolated villages for food or water, logwood camps, looking for local guides or information.
The Spanish could be looking for Cimaroons, escaped slaves, indians, foreign hunters such as the original bucanneers.
Pirates careening make a good scenario. With the ship heeled over for cleaning, the pirates could make a temporary log/earth fort to over seas the defence. Several were captured while careening.
Treasure hunts are always exciting scenarios, though usually non historical. Grab thou treasure map and go at it I say!