How many nights would be enough for my daughter and wife to visit Bacharach? Would 2 be enough? Also is there a direct train between Amsterdam and Bacharach?
Bacharach is a small place, so with one full day there, you can see it well, and even a neighboring town, too. How to Look Up Train Schedules Online gives you the DB train schedule link and tips for using it. Just request your two end points, from Amsterdam to Bacharach.
It used to be that the fastest route from Amsterdam to Bacharach was by ICE to Köln, IC from Köln to Koblenz, then a regional train from Koblenz to Bacharach. Looking at the schedule today, it looks like the fastest route is ICE to Düsseldorf, any train to Koblenz, regional train to Bacharach.
Discounted, advance purchase Europa-Spezial fares are available for these connections. If you go through Köln, you might want to spend a few hours, plus/minus, there. You can specify a fixed stopover with the Europa-Spezial fare, but since an IC from Köln to Koblenz is train specific, you might want to leave yourself open to a longer stay. You can do this by using the Means of Transport function to use a regional train from Köln to Koblenz. Regional trains are open on a Europa-Spezial ticket, as long as you complete your journey by 10 AM the following day (Vor- und Nachlauf rule), so you can spend longer in Köln and still use the ticket for regional trains from Köln to Bacharach through Koblenz.