Decide how you want to book tickets. It's easiest to do so online, but you can also book over the phone or in person at any number of train stations throughout Bulgaria (specifically in Sofia, which is the central train hub of the country).
Book tickets online through the Rail Europe Web site (see Resources below). You can also book by phone at 1-888-382-RAIL. The journey will be inexpensive to moderately priced.
Select a seat type that ranges from one standard seat to an entire sleeping car to yourself and your family. Sometimes these larger, bedded areas are the most comfortable and most affordable arrangements for a small family.
Check out the Bulgarian State Railway Web site for information on train schedules and traveling regulations (see Resources below).
See the Hellenic Railways Organization Web site for similar information on Greek policies and travel standards (see Resources below).
Choose the best dates and times you wish to travel across the country, keeping in mind the peak times of travel are in the spring and summer when the weather is more forgiving and tourism picks up.
Follow up with your travel agent or online booking Web site and retain all confirmation numbers and ticket itineraries.
Plan your time in Greece with information from the Greek National Tourism Organization (see Resources below).