Connection: According to Wikipedia, the Hagen railway station of category 2 is one of the most important railroad points in Germany. Within the VRR (Ruhr area and parts of the Rhineland, Düsseldorf), you benefit from the low-priced, interconnected tariff. For example, you can achieve the following goals with the ICE or Reginalexpress:
Dortmund Main station: 21 min (RE4, VRR fare), Stadium Signal Iduna Park: 28 min (RB52, VRR tariff)
Essen main station: 38 min (RE16, VRR tariff)
Düsseldorf Main station: 44 min (RE13, VRR tariff), Messe: Underground connection via Düsseldorf main station
Cologne main station: 46 min (ICE 952), trade fair: 55 min (RE7 NRW tariff)
Use the timetable information at www.vrr.de or www.bahn.de to find a suitable connection.
By car: You can reach the A1 and A45 motorways within a few minutes. Use the route planner from Google: