The answer depends on both time and wealth.

The First and Second Crusades took the overland route through the Balkans and Anatolia, but the failure of the Second Crusade, picked apart on the journey, and the relative success of the English and Low Countries contingent, who came by ship, forced a re-evaluation. All subsequent crusades went by ship, a contributing factor to the disaster of the Fourth Crusade, where the crusaders ordered more ships than they needed.

If you were with an army on a later crusade, you'd probably go by ship. Even if you were relatively poor, you were probably in service of a lord who would be paying for it - the maintenance of an army was part of the devotional act.

There were many reasons to go on crusade even if you were not a member of a numbered crusade, so your method of travel in this sort of circumstance would vary with your personal wealth and other factors.