(theres a typo..i meant 9pm, not 9am. sorry)

The #21 Texas Eagle train arrives in San Antonio (SAS) at 9:55 PM.
On the left side of the Amtrak Page there is a link to click for rental cars and Hotels. There are 10 hotels within 0.4 mi.
of the San Antonio station.

Have never taken the train to SA as I live here. Can tell you that walking from the station to the Menger takes probably less than 30 minutes, maybe 15 to 20; it is about 5 blocks. It is not the most scenic area but is safe. Years back the area was a little dicey but that has changed a lot with expanding development.
The downtown trolley is great for touring around (there are two routes that make fixed loops) but not the best option to get from the train station to the Menger- walking is probably quicker, or grab a taxi if you have much luggage.
Not sure when in Autumn you plan to visit but keep in mind that it can still be plenty warm and even humid in early fall here in SA. Suggest you have a look at the information at www.visitsanantonio.com
Oh, and bienvenidos!

I have a non-driving friend who occasionally takes that train from near Waco to north of New Braunfels. It's NEVER on time and usually takes (on average) twice as long as it would for us to drive it. This is regardless of what the schedule says. She was told on the last trip (by an Amtrak train attendant) that's because Amtrak shares the tracks with other train lines that can call priority on the tracks, meaning the passenger train may have to wait for other trains to move past.

That being said, she enjoys travelling that way, as long as she's not worried about when she actually gets there.