Commenting on the pasuk, "VaYavo Avraham lispod l'Sarah v'livkosa," the Midrash asks where Avraham was coming from. The Midrash offers two answers: 1) The well known answer cited by Rashi that he was coming from the akeidah; 2) He was coming from the burial of Terach. Ramban writes that in his opinion there is no basis for this question. The word "vayavo" need not mean literally moving from one place to another, but may simply indicate taking the initiative to start a new project. Ramban cites a number of examples to prove the point. Aside from this linguistic criticism of the Midrash, Ramban takes issue with the Midrash for another reason as well. Surely Avraham and Sarah were not living in seperate places -- why did Avraham need to travel from some other location back home to mourn for Sarah?
The Sochatchover tries to reconcile the Midrash with the Ramban. He suggests that the Midrash does not mean Avraham physically journeyed from the akeidah or from burying Terach to mourn for Sarah. Rather, what the Midrash means is that Avraham psychologically moved / travelled from a midas hadin mindset back to a chessed mindset. The potential offering up of Yitzchak as a korban is the antithesis of mercy; the act of burying Terach, kibud av, stems from the midas hadin that obligates hakaras hatov to parents (see Maharal, Tif Yisrael 42). This psychological reorientation necessary to begin the new task of burying Sarah is the same sense of "vayavo" which the Ramban understood al pi peshuto shel mikra.
I like the idea of reading the Midrash as a psychological journey rather than a physical one, but would like to suggest a slightly different approach that also explains the two views -- was Avraham travelling from the akeidah or the burial of Terach -- in the Midrash. The common denominator between these experiences is that they both were encounters with death. Terach had his shortcomings, but ultimately he came to do teshuvah after living a long and full life. In the end, I imagine Terach left the world somewhat fulfilled -- he recognized the truth and value of his son's mission, he lived to see his son's success, and he achieved personal redemption of sorts in teshuvah. The akeidah brought Avraham face to face with an entirely different type of death experience, namely the threat of losing Yitzchak. Imagine the hesped that would have been! -- Yitzchak cut down in his prime, so much potential that could yet have been realized, so much more that could have been achivieved had he been given the time to do so.
Which encounter with death did Avraham have in mind as he tried to relate to the loss of Sarah? On the one hand, Sarah had lived a long life, a fulfilled life. Perhaps, like with the death of Terach, Avraham could take consolation in that fact as he came to mourn her. On the other hard, who knows how much more Sarah could have achieved had she lived even longer? As old as Sarah was, as much as she had achieved, perhaps Avraham approached her mourning with the same sense of loss as he would have approached the loss of Yitzchak -- as much as was achieved, Avraham may have yet viewed Sarah as still in her spiritual prime with so much more to offer the world had she only had more time to do so.