Adding confluences is trivial, but I think it will break my bridges...
Why? You think it will randomly place a bridge on the merging point sometimes? I think it will be possible somehow to prevent merging area getting a bridge. I don't exactly know how you place the bridge on the map but I do think it won't be that much too random, there must be some excluded areas so I guess it will be possible to exclude that very problematic spot as well. Anyways, thanks for attention.
To place a bridge is harder than it seems. Initially the generator could place several bridges over a river, but it often produced weird configurations with a road changing sides back and forth. With two rivers I will have to allow multiple bridges again and there will be even more opportunities for the generator to build something silly.