"I am going to Germany next week."
Translation:Ik ga volgende week naar Duitsland.
Ik reis = I travel / am travelling
While I'm going to Germany next week may include some amount of travelling (getting from a to b) the distance etc. may not warrant the use of to travel.
To give a bit more context, a lot of people live close to the German border and might go to Germany for some shopping. For some the shop in Germany might be closer than a similar shop in the Netherlands. So when they are going to Germany using reizen is similar to saying you are travelling to the nearest shop etc..