That would be nice to visit Konstanz again.
It's a pretty nice city to visit, and it's excellent for shopping (there were sales last Saturday, it's probably still on).
You're very welcome if you have Thursday free (or ensure it is) and specially if you're a native German speaker (need to improve my spoken German ;))
Planned train is 9.17, The schedule can be set a bit later or earlier if it fits better.
There is a direct train every hour, at xx.17.
Return trip cost (with halbtax) is around 30-.