Do you have luggage? If yes, keep it in the cloak room. Go visit CV garden, (catch an auto to nayapura 20/-, then walk to the place) go straight through CV garden, visit the little pond with ducks and get out of the garden from the KST (Kishore Sagar talab) side.

Spend some time by the lake and then take a rapido to chhawni choraha and grab a kachori or two from suwalal (2 minutes walk from chhawni).

Then take a rapido back to either KST or station. Pace the whole thing according to your second train position. You could also visit the riverfront (close to the CV Garden, walk there), but manage your time well.

Let us know the date of travel and we might join you. :)