Eurail pass and Rail travel

Before you do anything else, read this excellent summary from the Man in Seat 61, who is quite a specialist in rail travel. When you do, you will see that a pass would most likely be a huge waste of money for your trip. If you can commit to non-refundable, non-changeable tickets, you can buy these in advance from The Bahn website. This German Rail website is also the best place to get European rail schedules, and prices for trains within Germany. Others here will know the family specials, but I can say that for my September 2012 trip from Berlin to Dresden, the full fare for 1 was 39 euros and for 2 was 78 euros, while the advance purchase fare was 19 euros for 1 and 29 euros for 2. So, on this roundtrip, my mother and I saved 98 euros (about $130 at the time). Then, for our daytrip from Dresden to Goerlitz, we used a Sachsen Ticket, at 28 euros for both of us for the whole day. A separate issue: were you planning to stay in Frankfurt and use it as a base for daytrips to Munich, Heidelberg, and Bastogne? (this is implied in your post, but not clear). Munich and Bastogne are too far to be daytrips from Frankfurt (the Bahn website shows Frankfurt to Bastogne as over 6 hours with 2-4 changes!). A much better plan is to fly into Munich, go to Frankfurt and Heidelberg, and end in Belgium (flying out of Brussels). Yes, the flights may "cost more" and you'll have to change planes, but you'll be where you want to be, and avoid wasting time and money backtracking.

Thank you for your reply. We plan to stay in Munich for almost a week and probably in Bastogne for two days. After much research today my wife and myself have decided on renting a car during the trip for the ease of side trips, scenery, and freedom to change our plans in the last min. The cost from what I have seen even with insurance is close to to even cheaper then rail.

tolls (I don't believe there are any in Germany or Belgium, Tolls (quite high) on the tunnels under the Scheldt around Antwerpen in Belgium.

When calculating the cost of a car, don't forget to include the cost of gasoline in Europe (MUCH higher than in the US) and tolls (I don't believe there are any in Germany or Belgium, but there are, in one form or another, in Austria, Switzerland, and France, should your itinerary route you through any of these). And be sure you're looking at a car that can hold 4 people plus their luggage (most less expensive models in Europe will be too small). I'm not saying you shouldn't go by car (especially for 4 people), but do compare apples to apples, to avoid nasty surprises.

Wait, are you doing daytrips from Frankfurt,,or spending a week in Munich? You said both. You won't want a car in Munich, with parking hassles and costs. There are some kind do tickets for travel in Germany that cover up to 5 people traveling together. Mounds good if they will work for you. You might Start another topic to ask about those. I forget what they are called, but lots of people here have mentioned them.

The most popular of the tickets that work for multiple people for the day are called Laender tickets (a "Land" is a German state). I used a Sachsen ticket within Saxony (for the daytrip to Goerlitz described above), and Bayern tickets are often discussed here, as they work for all of Bavaria and even include Salzburg. They cannot be used before 9 AM on weekdays (no restriction on weekends). They cannot be used on high speed trains. Until about 6 months ago, these tickets had a flat price for up to 5 people. Now there's a base price for the first person, and it's about 4 euros extra per extra person, up to a maximum of 5. They remain a great deal. There are also tickets that work for multiple Lands, and that cover a whole weekend. However, when going longer distances, the inability to take high speed trains becomes more of an uncomfortable restriction.

Frankfurt-Munich: If your younger son will still be 14 when you take this trip, he will ride free on long-distance trains in Germany. If you book well in advance (up to three months allowed) on the German Rail site, you can get a discount fare of €69.00 for all four of you together. Day trips from Munich: A Bayern-Ticket provides unlimited travel all day long on regional trains plus the S-Bahn, U-Bahn, and buses in Munich on the day the ticket is valid. As Harold said, it also will get you to Salzburg and back to Munich. It's good after 09:00 on weekdays and anytime on weekends. For four of you it will cost €36.00. No need to buy the ticket in advance. Munich-Heidelberg: If you book well in advance on the German Rail site, you can get a discount fare of €69.00 for all four of you together. Munich-Bastogne: Book Munich-Cologne on the German Rail site to get a discount fare of €69.00 for all four of you together. Book Cologne to Liège-Guillemins on the German Rail site to get a discount fare of €57.00 for all four of you together. The fare for the bus from Liege-Guillemins to Bastogne is €17.90/person. You can book tickets online on the Belgian Rail site.