Go inside the main building to the check-in desk and you'll be able to check your luggage there
I get there an hour early, but that is me. I hate to be late; it has to do with potty training and the military when I was older.
At least an half hour but preferably sooner than that
At least 30 min to be safe. 20 min and you will get scolded but should still check them.
When I rode the Capitol train from bayarea there was no baggage check going on. That might have change Post holiday so check out on line ,in person if can. Different routes might have different rules
At least 30mins. Not all trains have checked baggage.
Unsure my best guess would be an hour
Thanks! Your answer is awaiting moderation.