I am attending 2 Bundesliga games at Gladbach & Schalke. Would my match ticket get me to the stadiums for free. I am staying in Dusseldorf.?
Düsseldorf, Gelsenkirchen (Schalke) and Mönchengladbach are parts of the VRR (http://www.vrr.de/img/sites/kundencenter/VRR_map_2016.png), and the tickets of both clubs are valid for bus, tram and train in the VRR-Area at the day of the match (only regional trains, no IC, EC or ICE).
In Stuttgart only in 30 km. I think you must buy a Ticket