The NEW right of way is only about 35ish miles. They MAY bury only a portion of this. The remainder 3/4 of the state will transit along existing right of ways. It will not be buried.
Pages 3 through 6 give some indication of the challenges of burying large electrical transmission lines. Note this is a line of approximate 1/2 the power flow.
http://www.nstaronline.com/docs3/openaccess/roe-volume-4.pdf