travelling and wandering
Teams: KV Oostende, Rosenborg BK, Norway, Israel, Turkey
RC Mechelen have a die-hard support of not much below 1000 fans and they are very vocally present so you can definitely see them as a very large fanbase for D3 norms. And unlike Liege, they have a beautiful stadium with an amazing main stand, this stadium belongs in D1 in fact.
But... both Mechelen teams share one illness: hooliganism. While the majority of fans of both Racing and KV are great and loyal fans, both clubs have a minority of scumbags who cause trouble everywhere they come. Racings hooligan problem is even bigger than the one of KV who have taken better measures to control their issues. So Racing Mechelen is a great day out when it comes to stadium and atmosphere, but unfortunately you will see a minority of idiots who should be banned from football stadiums... In that aspect, Liege is a much nicer club as they have no specific hooligan issue.
Also note that in D3 a few other clubs have a nice fanbase: Aalst (who also have a little hooligan problem but the majority of fans are very loyal and nice, and they have an incredible amount of fans for D3 standards), Union St Gilles, Rupel Boom (great stadium and a very nice set of fans), and to lesser extent La Louviere (not the nicest stadium but their fans are very friendly or at least they always where when KVO travelled there)