When it comes to the traveling methods, we will focus on the First and Third Crusades, with special attention for the 4th, as it was the transportation situation itself that greatly contributed to the disaster involved in that misadventure.
The First Crusade had no single leader, but rather a league of nobles representing different nations and royal houses. Therefore each took different routes, with Godfrey choosing a land path and meeting the others in Jerusalem and others marching across Europe to gather in Constantinople (while committing many pogroms along the way...)
The Third Crusade largely ended in an impasse between Richard the Lionheart and Saladin, but it is often the most recognized crusade due to all the famous rulers involved (Frederick Barbarossa of the Holy Roman Empire, Philip Augustus of France and others). This conflict involved both land and sea, with France and England bringing their troops by sea and Germany marching by land, during which Frederick Barbarossa fell into a river and drowned, resulting in the German forces never reaching the Holy Land.
The fourth began with the Pope recognizing that they needed a large fleet in order to arrive in a timely manner for the Crusade, lest their forces be divided. This careful foresight resulted in the sack of Constantinople due to the actions of Venetian merchants who had promised to deliver crusading troops to the Holy Land via ship.
Running up a huge debt while waiting for the ships to be built (perhaps deliberately), the Crusaders found themselves in the capital of the Byzantine Empire. Manipulated by the doge of Venice into becoming involved in a dynastic struggle after he promised to cancel their debt (should they be successful) and ferry them the rest of the way to Jerusalem. Needless to say, this resulted in the sack of the city, perhaps the intention all along. While the Crusaders seemed to revel in the pillaging, historians wonder if they were complicit with the merchants in exchange for a share of the plunder. Either way, the 4th is likely the best example of the tenuous nature of sea travel to the Holy Land, especially if the proper contracts were not in place beforehand.