This raises another interesting question. How many did make it back? Besides the vast amount who died, wouldn't a lot of Europeans want to stay in the Middle East?

Travel during this period is an interesting topic.

I'm no expert (except a bit on seafaring) but a recent book in Finnish, Matkaopas keskiajan Suomeen (Travel guide to Medieval Finland) by Ilari Aalto and Elina Helkala does have fairly good overview of how land travel happened. The book focuses specifically on Finland but I guess the basic principles were fairly similar around the world.

I'll skip the seafaring part because it was in principle simple: you looked for a ship bound to where you wanted to go, and tried to bargain your passage one way or another. Then you hoped the captain was honest and there were no shipwreck or pirates or enemies along the way.

The land travel part is more interesting. Since there were no maps (in the sense we understand them), few if any roadsigns, and the roads themselves might be somewhat... interesting, travelers generally navigated from one village or landmark to another. They would probably have a general idea of the direction they'd need to travel, and then they would simply ask the locals or the passers-by for directions. These would most probably be unaware of the whole route, but they could provide directions to the next village etc., where the process could be repeated. Often the easiest way was to follow major roads or landmarks such as rivers.

Over longer stretches and particularly in areas of less dense habitation, guides were probably very important. In medieval Sweden (which Finland was part of), there were special guides or ledsagare ("roadsayer") who knew their area fairly well - or at least were supposed to. A traveler could hire these guides to show the way.

You can imagine that this system had significant potential for all kinds of mischief being played on the stranger. It would be interesting to have an estimate of how many did make it back; I'd guess a fair few would have succumbed en route.