Not up to standards
This hotel shares a parking lot with the Amtrak station which makes it convenient for over night stays for a train that leaves at 7am. It's poor quality, however should make you think twice. 
First, they do not offer rooms with 2 queen beds, which makes sharing a bed, even for children over 6 a problem. The furnishings are old an the rooms are dirty. We pulled the old comforters off the beds and left them in a corner. The pull out sofa had a half inch foam mattress that sunk in the middle. Both beds also sunk in. 
And if u think it would be great for just overnight before u start your train travel, be prepared, this is not a budget hotel! Prices start at over $150 a night for a single not including the high hotel tax San Antonio is known for. The convenience of walking to the train in the morning does not outweigh the miserable night we spent there. There are so many wonderful hotels within a mile of Sunset Station, skip this place and use a cab or hotel shuttle.