1. It's not impossible - impractical as it is, I think you (at least) can walk between B and C via Ditmars Blvd and crossing the GCP twice. (Aside: there are even citibike docks on Ditmars close to B and C.) There's the Port Authority-run shuttle between terminals, between B and C following the same pattern as the Q70, so that's another option to augment frequency