the new Warwick station is geared for the commuter, not so much for airport users. Having said that, it will surely be an asset and be used by some (admittedly a limited number of) air travelers.
the express buses from TF Green go to Kennedy Plaza where one has to either walk the 2 blocks (partially covered via the tunnels under the old train station buildings and memorial blvd/waterplace), transfer to the RIPTA gold line, or transfer to RIPTA bus #50.
Peter Pan reduced the weekend one way fare between Providence (city, not airport) to $5.00. The weekday fare is higher. This is only good to South Station. While all those buses continue to Logan, the one way fare there is $22.00 (roundtrip is $40.00).
8 weekday trains is a good start for a brand new station. If pasengers use it (commuters and/or airport) then they will add more. The revised RIPTA network will piece it all together to fill in the gaps in the train schedule to make the airport stop both convenient and afordable for many differant types of travelers, and not just between TFG and Providence/Boston.