Looking for a place near Alstadt for lodging for solo traveler.
You will get a better response to your request if you place what you need in the Destination section under Germany.
I've been to Dusseldorf several times and am fortunate to stay with family. So I'm unable to make any recommendations. The Alstadt is a fun place.
Almost every trip I end up in Düsseldorf for at least a few nights as it is so convenient train-wise and as a public transport junction.
I'm a regular in a 3 star hotel just opposite from the train station. The hotel "Bismarck Hotel" is on Bismarckstrasse, has en suite facilities , an elevator, accepts a credit card if you prefer that method over cash payment, a nice breakfast buffet. The ambience is old school. The paintings and wall photos attest to that.
About a 20 minute walk to the Altstadt, straight up Bismarckstraße.