go find a map of the Amtrak stations in San Fran and im sure the map will give you an answer! good luck with that!
2.5 days
You cannot get a train directly to the airport. However, you can get a train from NY Penn Station, and your best bet of the multiple Amtrak stops in San Francisco would be to stop at the Caltrain Station and catch a cab to the airport (11.7 miles, 17-20 minutes depending on traffic).
San Rafael Arcangel and San Francisco de Solano
You could try going by Amtrak. San Francisco has about 5 to 7 (somewhere around there) Amtrak stations, and San Diego has one too. I'm not sure about the route since there's more than enough stations in San Francisco, though.
San Francisco International Airport - SFO - - BART station - was created in 2003.
To get to the San Francisco Zoo, you will want to take the Amtrak train that stops at the corner of Fourth and Townsend Streets. You can walk to the zoo from there.
Although Granby is physically the closest station to Loveland, Denver is probably the best year-round choice. From Denver, you can take the California Zephyr east to Chicago or west to San Francisco.
Mt. Pleasant, IA. From there, you can take the California Zephyr east to Chicago or west to Denver or San Francisco.
Greyhound is one option. Another is taking the Amtrak Pacific Surfliner to Los Angeles, transferring to the Amtrak Coast Starlight, and taking a bus from Emeryville to San Francisco.
Emeryville. From there, you can ride the California Zephyr to Salt Lake City, Denver or Chicago, the Coast Starlight north to Portland or Seattle or south to Los Angeles, the California Coastal Routes between Sacramento and San Diego, the San Joaquins to Fresno, Bakersfield or Southern California or the Capitol Corridor between Sacramento and San Jose.
2.5 days
South San Francisco - BART station - was created in 2003.
You cannot get a train directly to the airport. However, you can get a train from NY Penn Station, and your best bet of the multiple Amtrak stops in San Francisco would be to stop at the Caltrain Station and catch a cab to the airport (11.7 miles, 17-20 minutes depending on traffic).
Angel Island was the main immigration processing station in San Francisco.
San Rafael Arcangel and San Francisco de Solano
Little Rock. From there, you can take the Texas Eagle north to St. Louis or Chicago or south and west to Dallas, Fort Worth, San Antonio or Los Angeles.
You could try going by Amtrak. San Francisco has about 5 to 7 (somewhere around there) Amtrak stations, and San Diego has one too. I'm not sure about the route since there's more than enough stations in San Francisco, though.