Here some details of the trip:
1) Departure from Universität S-Bahn (to Stuttgart Hbf) at 08:34 -- meeting at 08:25 at the platform.
Departure from Stuttgart Hbf (oben) to Bad Friedrichshall Hbf at 09:08 -- meeting at 9:00 at platform 7.
2) The salt mine tickets cost 12 euros for adults, 10 euros for students. You can pay for them with a card.
3) It is recommended to take a light jacket/overshirt/etc. since it can be chilly in the salt mine. It is also recommended to wear convenient shoes because we are going to walk a lot. However, the salt mine itself is rocky and not dusty, therefore you should not worry much about your clothes getting dirty (e. g. as it could be in case of hiking).
4) Estimated lunch time -- from 13:00. The beer garden accepts cards as well.
5) Estimated arrival back to Stuttgart Hbf -- around 18:00.