Here is another way to look at the continguous space that Harvard has available to use for construction of the Science Complex. This looks at only the 19 acres south of Western Ave and exlcludes the triangular parcel closer to Hopedale and the two lots on the north side of Western Ave.
I am not suggesting that this is exactly where the parking would be situated. Maybe it would be on some other portion of the lot or maybe it would be in multiple smaller lots in different parts of the larger site.
But the point is that there is a lot of space (8+ acres) left over after accounting for the building site and the parking. Until Harvard can explain why this doesn't make sense, it seems that therer is no need to park any cars on the Sears site or elsewhere that would reduce the quality of life for people living on Hopedale St, Windom St, or elsewhere in the neighborhood.