While I agree that a bridge would never happen, this did make me think about where other bike ped connections would work. I don't think in between makes sense - too poor connections to paths, roads and population centers. A seasonal, good-weather only, water taxi esque ferry service bouncing between the Buzzards Bay and Bourne canal access parking areas underneath the rail bridge? That may have merit given presumably low capital and operating costs - especially if you get one of those electric fully autonomous mini ferries they're testing in Trondheim. Then again... With a more robust CR schedule you could just hop a train over the bridge.