Llama
TS Member
It should be a relatively easy trip from Phantasialand to EP but there are a few ways to make it easier. It looks like the majority of it will be via ICE train from Cologne to Offenburg, so as long as you're at the Cologne station at the right time you can take the regional train there from Brühl at any time prior to the connection. The regional trains run frequently and are generally very reliable so you can easily give yourself a lot of buffer time just to make sure you make all the connections. I would also recommend getting to Cologne a bit earlier to walk around the cathedral, it's directly outside the central station and is one of the most incredible things I've ever seen.
Also make sure to book a seat reservation for the ICE leg, it's only a few euros and that way you're guaranteed to have a spot to sit down. Cologne station is pretty big but the DB app will tell you which platform you'll depart from, and once on the platform they usually have signage matching the wagons to the platform areas so you'll even know exactly where to wait.
For additional info I can recommend the wonderful Man In Seat 61 page. More information than you'll ever need about the how-to of European train travel
Also make sure to book a seat reservation for the ICE leg, it's only a few euros and that way you're guaranteed to have a spot to sit down. Cologne station is pretty big but the DB app will tell you which platform you'll depart from, and once on the platform they usually have signage matching the wagons to the platform areas so you'll even know exactly where to wait.
For additional info I can recommend the wonderful Man In Seat 61 page. More information than you'll ever need about the how-to of European train travel