There is a north/south walkway on the first level of the parking structure to access the escalators; it goes from the 94th street former bus entrance to where the buses currently pick up and drop off passengers. There is no need to navigate around vehicle traffic. Also, abaheti mentioned a "younger person with carry on only", not "a kid", in addition to his elderly mother.

As I wrote above, it's a good alternative, however, I prefer the Economy Parking structure to the Transit Center for picking up and dropping off passengers, and have used it numerous times for that purpose.