I looked at the trains site, and it doesn't seem very doable to go to Speyer alone by train
Speyer (which is great place to visit in it's own right) is on the Rhine and quite far away from Franconia (where Zirndorf, Nuremberg, and Bamberg are). I don't think that I want to visit all these places in one trip. I'll set off from Munich to the event in Zirndorf, will probably stay the night in Nuremberg, and
perhaps include a visit to Bamberg, but that's it, so will return to Munich on the second day.
I imagine that you want to visit the Oliver Schaffer exhibition in Speyer? Sounds like fun, but I need to keep things brief, so I'm not going there. Joint travel to (and from?) Zirndorf is however definitely an option!
Things haven't yet progressed to the commit-and-pay phase at KW yet. That should happen soon, I guess.