Gardner's a much-inferior route. The yard is small, and it's operationally inefficient for PAS to have to play fetch from the real auto facility in Ayer to make the exchange. For P&W it's 25 miles of track they have to maintain to relatively good quality to transport racks, and there's absolutely no on-line biz justifying its existence beyond that. With the G&W buy both parties are probably going to look at their options for relocating the interchange to some more opportune place their systems intersect.
The Worcester Main may or may not be one of the places they look at. All depends on whether PAR or its successors are warm to the idea of letting a third wheel in P&W (not NS) have overhead trackage rights on its Worcester Main to do set-offs at Hill Yard instead of Gardner. If MassDOT floated some dollar bills for substantial track upgrades to bring the players to the table PAR would probably consider this (and have to consider this), because if the system is partitioned from PAS the Worcester Main becomes part of 'the' main and one overhead round-trip per day is a small barter for somebody else buying them a brand new railroad. Pure speculation at such an early date where the G&W purchase hasn't even gone in front of the STB, but that's the kind of all-options-on-table sifting the players will look at post-transaction about how to mutually optimize that interchange. If NS and P&W can find a mutually beneficial way to trim Gardner, they'll do it because it's subpar efficiency to interchange there.
Providence is simply way too small and way too close drayage distance to Ayer via I-190 and MA 146 to register on NS's radar. P&W's figured out the ports thing and is starting to do pretty well milking Davisville, Providence, and New Haven. Good on them, good for whatever PAS can schlep from that in interchange loads. NS certainly isn't displeased with the auto growth. But RI freight volumes are zit-sized for a Class I's interests just like CT's, VT's, and NH's are. Portland, being *just* at the outer limits of optimal drayage distance, is some interest as exploitable leverage via a second-party. But if NS has pretty firmly drawn its border at Ayer and shown little to no interest in sniffing around Div. 2, then the answer to every other question in the Norfolk boardroom is "Providence, Where?" Doesn't register for internal strategy at all.