Take any IC train to Rotterdam Centraal a lot of them do not have steps to enter. However the Intercity Direct has two steps if I am not mistaken.
Enter the train with a Bike or Wheelchair symbol usually there is a four seater nearby to sit in comfort and to keep an eye on your bags.
I've tasted the Kroket on the Rotterdam last week and was not impressed. My guess is that these Kroketten have a low percentage of Veal. I think the use of beef will give meatier texture. I prefer a Beef Kroket over a Veal Kroket.
Depending on your starting time, I would do the shopping streets, ea Lijnbaan, first, those are more less deserted at night. End at Markthal for a bite and maybe getting some snacks.
Take a Canal cruise, or visit the Big Museums around Museum Square. The Rijksmuseum for the Nightwatch or The Van Gogh Museum. Next to the Gogh is the City Museum for modern art. Anne Frank house is also an option. All the musea are easily reached by public transport. Reservations for the Musea are recommended especially the Anne Frank house.
I am familiar with the location, not the hotel. Location wise it is perfect. Close to Public Transport, Jordaan district and the Museum district is just a couple of stops away. I have been in another Westcord hotel, they had a clean pleasant vibe.