My wife and I are on the September Stockholm to Amsterdam cruise on Sirena. We dock in Rouen, France, at 6 a.m. Oct. 14. The ship leaves Rouen at 5 p.m. If we figure to be back on board at 4 p.m., is it still feasible to take the train to Paris and back? Doesn't seem worth it if we only have a couple hours. Thoughts?