In medieval times, there was no Department of Transportation to keep up the roads. The condition of the roads in general was poor, which made horseback riding difficult. There could be no signs or wrong signs. Travellers often had to pay a toll to use the few well-maintained roads.
Travelers also had to deal with the danger of bandit attacks, which were more common at night. Bandits favored groups of travelers that seemed small enough to take on, as well as stragglers from larger groups. Another method of thievery was the confidence trick. A thief would make friends with travelers via the disguise of a priest and then rob them.
Though inns existed along the way, poorer travelers had to live off of the environment, hunting and gathering their food. This posed such dangers as exposure due to bad weather, difficulty finding food and putting up with bad food. Finding food could be difficult, even if you made it to a village or city, as one place could have lots of food, while another was stricken with famine.
Also, the geography of an area that a traveler traveled through posed problems. They might face crossing mountains and trying to overcome obstacles such as rivers. Added to this would be weather conditions that could make the terrain more difficult to cross.
Sea travel was easier than land travel. However, overcrowding, rats, bad food and fleas all contributed to make boats an unhealthy place to be. Seasoned travelers brought a small apothecary with them, examples of which are figs and ginger. Anyone unlucky enough not to get a spot to sleep on the deck had to sleep in the hot and smelly space beneath the deck.
Another danger that travelers faced if they traveled by boat was pirates. Piracy was especially prominent in the Mediterranean Sea.
Weather is a natural danger that might happen to a ship. Winter was the most dangerous time to sail, due to such things as snowstorms and rainstorms and reduced visibility due to foggy and cloudy weather. If something did happen to the ship, people might not survive because swimming was not a common skill in the Middle Ages.
The dangers of a trip depended on the route to a degree. The most dangerous trip was going to the Holy Land.
Even in Medieval times, people wrote guidebooks for traveling. A book written in the 1100s titled "Guide for Pilgrims to Santiago," provided travelers with such information as roads to use, places to stay, town names, places to stay and useful items such as conditions of rivers.