Thanks Alan, I have changed reservations to the Courtyard by Marriott South Boston. Looks like a 13 minute trip by Red Line T, including walking 2 or 3
very long blocks. Will have to check if Courtyard has a shuttle to the station.
I know that they have a shuttle, just not sure if they charge for it. I saw something, I think in the hotel's book in the room, that suggested that there might be a charge for it. No idea on the cost. But calling the front desk should answer all questions for you.
If you do decide to walk it, when you come up the escalators you'll want to make an immediate 180 and walk to Dorchester Avenue, which would be the street in front of you. If you come up the elevator, turn right upon exiting and walk to Dorchester. Dorchester after a short half block walk leads to an odd 6 point intersection. There will be a Dunkin Donuts on the corner. Cross from the DD over Southampton/Preble Street to the bank on the other corner. This is Boston Street. Follow Boston as it crosses over the Red Line tracks and a major highway. Shortly after crossing the highway, you'll turn right onto the first street you come to on your right. Note, you actually have to cross Washburn Street to get to the sidewalk. The sidewalk is only on one side of this street. The hotel is visible in front of you.
This map should help to give you the lay of the land as it were.
An interesting side note, if you turn right at that DD and walk down Southampton just about 2 blocks, when you're up on the bridge you'll be able to see Amtrak's Southampton Yard where all the trains in Boston go for work & storage.
I've always found this hotel to be clean, with decent accommodations. They offer both a full service breakfast or a buffet, your choice.
Andrew is the second stop after you leave South Station, the first is Broadway. The actual ride is maybe 5 minutes, if that. Consider buying a day or even a 7 Day pass, depending on just how many trips you expect to take each day. A one ride ticket is $2.00. A 7 day pass is $15. So if you expect to hit a subway and/or a bus at least 7 times while you're in Boston, you'd have spent $14 on single ride tickets. If you're going to be there for 3 days, then you only need to take 2.5 rides each day to save money with the pass.
You can buy that pass either from a ticket vending machine down by the subway entrance, or a TVM on the Amtrak level, or from a live agent at the Commuter rail ticket windows.
The Red line offers two services, one to Ashmont and one to Braintree. At South Station both operate on the same track. You do NOT want to go to Alewife! That's the wrong direction.
The two services split at the JFK/U Mass station, one stop further than you need to go. So you don't care which Red Line train comes first, you can board either one to get to Andrew.
PS. The fare information is correct at present. The T is however considering a major fare increase that could be in place by the time you take your trip, so you'll have to check things again as you get closer.