www.bahn.de

Train from Prague via Dresden and Leipzig to Halle, change in Dresden and possibly (depending on actual connection) in Leipzig. Takes between 4:17 and 5:36 hrs.

There is a slightly faster train, with only 1 connection in Dresden, leaving at 16:29. It takes 4:06

Other than that, the trips with 2 connections through Dresden and Leipzig are generally a bit quicker than the single connection through Dresden.

Thank you so much for your help! Is it best to do 1st or 2nd class? What is the difference? Is it hard to make connections? Should she try to make a seat reservation or is that even possible?

Second class is fine but do make a seat reservation. They will tell you it isn't necessary but if she doesn't want to risk standing on a leg (of the trip, not her body!), make the reservation.

Think of 1st and 2nd class categories on trains in Western Europe as equivalent to First Class and Economy on airlines. If someone was paying for me to travel First class, I would, otherwise Economy is just fine.

If you know for certain which train you want to take, then the reservations are the way to go.

If you have trouble finding the link to change the language on the www.bahn.de site, just go to www.bahn.com and select "Other Countries" from the table. English pops up and you can book the whole ticket easily from there.