Just a quick test of the program TopoR. This is my Bloxorz cartridge, manually routed in KiCad:
And this is the routing with TopoR:
Looks very good, 100% routed, less vias (20 instead of 35) and shorter connections. I have to look in more detail into it how to specify different trace width for the power supply, but it is much better and easier than manual routing, or the KiCad auto-router. You can download a free trial of the program from their website, and a lite version with limited number of connections.