European Rail Travel - Germany Rail Advice

I will be traveling from Amsterdam to Munich by way of Augsburg on July 7. I have to catch a train in Munich at 11:30 p.m. The only thing I have to do is spend a few hours in Augsburg (husband born there). Anyway, I'd like to be able to stop at a castle or two along the way. How would I do this by rail? Should I travel to Koln or Koblez and then travel by ferry to Mainz, then going from there to Augsburg by train? All advice would be appreciated, including where to purchase tickets and whether to get tickets ahead of time. Thank you in advance.

I think you are under-estimating the time this is going to take.

Amsterdam to Augsburg is about eight hours... so if you want to travel from Amsterdam to Augsburg, spend a few hours in Augsburg and get to Munich in time for a 23.30 departure then there won't be time for any stop-overs or detours.

You can get timetable information, and buy tickets, at www.bahn.de