Rail Passes in many countries

You'll get the best advice if you provide specific cities/towns you will visit. "We will do as much night traveling as possible." I would discourage this approach on the basis of cost and comfort. A good sleep is your best travel weapon. 5 countries in 20 days? That's a lot. Why global passes? I'd look into 5-days-in-60 passes for Benelux, France, and Germany - about $400 each in the twinpass version, less for the kid. That will cover 5 major travel legs. You can reach Salzburg Austria without adding a country. Within Germany, travel on cheap daypasses; see the Rhine and Mosel regions south of Bonn for 29€/day on a Rheinland Pfalz ticket: http://www.vrminfo.de/en/tickets-and-fares/ticket-offers/rheinland-pfalz-ticket/ (similar prices for other states for similar tickets.) Then reduce travel time over the Alps by booking cheap flights to/from Italy. Right now, I see flights for 12.99€ on Ryanair from Frankfurt Hahn to Pisa, for example, for the week beginning 7/23.

That is helpful so far but let me try to answer your question. We are flying into Frankfurt, so we will take the train to Bonn from there to meet my daughter. I have other family in Hannover, so that is another train trip. We are debating going to Netherlands or not but the other cities we would like to see are: Paris, Rome, either Venice or Florence, possibly back to Hannover then to Frankfurt to fly out. Or maybe directly to Frankfurt, not sure about that yet. So at this point...arrive Frankfurt, train to Bonn (couple days), train to Hannover, then to Paris, then to Rome, then to Venice or Florence, then back to Germany. So at the high end possibly eight connects or as few as six. Does that help? I appreciate the advice so far.

Railpasses would be too pricey. I would piece together individual tickets for these journeys. See http://reiseauskunft.bahn.de/bin/query.exe/en for first 3 legs below; prices are for the three of you: Frankfurt airport - Bonn: 74€ on the direct IC train. Buy at the airport station. (You could buy in advance for less, but you would forfeit the ticket if you have a flight delay.) Bonn - Hannover: 132€, less with advance purchase (maybe 59-109€ Hannover-Paris: 198€ for 3 w/ adv. purchase Fly Paris Beauvais to Rome w/ Ryanair: price varies by day but maybe 150€ for 3 (plus transport to/from airports.) Train from Rome to Florence: 50€ ticket for 3 with adv. purch. at www.trenitalia.com Fly Ryanair from Pisa to Frankfurt Hahn: 39€ total for 3 tickets (plus transport to-from airports. Shuttle bus between Florence and Pisa, shuttle from Hahn to Mainz or Frankfurt, both near FRA.) That's about 650€ or a little over $800 or so total. You're likely to hit around $1,000 with airport transport, etc. All flights and the train tickets will be cheaper the earlier you buy - but make sure you can live with the itinerary prior to purchase as there would be penalties and forfeitures for changes.

One downside to the railpass is that you will need to buy a 1st class pass but your kids will get the student pass for 2nd class. So you'll wind up sitting in 2nd class all the time having paid for 1st class. Some of those long trips might just be better by flying. Inter-Europe airfares can be very competative and for train trips over 4-6 hours, flying also saves a lot of time, which can be just as valuable. As someone else has said, overnight trains don't provide much sleep or rest and can make the next day a drag. If your daughters (or you) are the type to get really grumpy with a lack of rest and comfort, then definitely re-think that. Overnight trains must for sure be pre-booked for summer travel. They do fill up, especially if you want your own cabin for just your family. You can pre-book on each country's rail website or through Rail Europe.

In Germany your 13-year-old daughter will ride free when traveling with you. Booked in advance on the German Rail site, you can get a discount fare ticket as low as €19.00 for Frankfurt airport-Bonn and that includes your daughter. What time is your flight scheduled to arrive? Bonn-Hannover: Booked in advance on the German Rail site, you can get a fare as low as €59.00 for the three of you. Hannover-Paris: Booked in advance on the German Rail site, you still can get a fare as low as €198.00 for the three of you on daytime trains. Or take the direct CNL night train. Discount fares are offered for various kinds of sleeping accommodations. Paris-Rome: Fly either Vueling or easyJet from Orly to FCO. While Ryanair's fares are likely to be cheaper, Beauvais is a long way from Paris and Ciampino also is an outlying airport. You'll have extra time and expense getting to and from those airports. Rome-Venice: The standard 2nd class fare on a high-speed EuroStar Italia train is €76.00. The best MINI fare is €9.00, but the allotted number of tickets at that price are long gone. The €19.00, €29.00, and €39.00 MINI fare tickets probably are long gone also, but you may be able to get a €49.00 MINI fare. Book at trenitalia.com. Venice-Frankfurt: Fly Air Berlin (one connection in Berlin) from VCE to FRA. Or take the CNL nght train from Venice to Munich and an ICE train from there to Frankfurt. Booked on the German Rail site, you can get discount fares for the entire ride.

Wow, thank you for all of the suggestions! Any others would be greatly appreciated. I will have to get on this and get a more set itinerary.

FYI, I have been working the past few days on my plan for trip at the end of July from Munich to Venice (overnight train) to Rome to Paris (overnight train). I have found several overnight trains already SOLD OUT except for just seats. If I were you, I would finalize the plan ASAP and book any overnight trains now. (btw, avoid RailEurope, it is more expensive for the same ticket than the other sites. Use tgv-europe and just be from 'Canada'). Deutsche Bahn is by far the most understandible site for schedules, even if the train goes no where near Germany.