The 1.2 miles in Framingham were paved in 2015. Construction of a 12-foot-wide multi-use path along the remaining 2.4 miles in Natick is being proposed. That includes a grade separated crossing at Route 30, as well as replacement of the CSX bridge over Route 9.
Update 9/10/2018: MassDOT has posted the project for construction, with the bids opened on November 27. Construction is expected to start in 2019.