Flemish/Flanders Red is also sour
. It has a little more of an oaky/sherry vinegar note compared to other sours you may have had. Rodenbach or Duchesse de Bourgogne are probably the most common versions in the US market.
I do recommend still going to Cantillon and doing the self guided tour and samples at the least. It's an easy walk from one of the major train stations (although not the nicest neighborhood). If you don't like their beer, no big deal. It's still fascinating to learn about spontaneous fermentation and to experience the full body experience that is the smell of the barrel room.
It sounds like the experience you're looking for is more along the lines of going to the Delirium Cafe in Brussels. Or Kulminator in Antwerp. I mentioned the two places in Ghent already. Cambrinus in Bruges is probably the best place there.
Unfortunately, pretty much all of the Trappist breweries are out of the way and you can't really "visit" them for a tour. It's more like go to our cafe/gift shop and buy stuff. Probably better off going to the beer bars and drinking their beers/getting vintage bottles.