The important aspect is that the transmission line is going in. Whether it is along the road or in the straightest route is secondary. No need to be concerned much about which path. The path for it is determined on what is most expedient cost and service wise.

Even though my background is electric engineering, I have nothing significant to add regarding economics of transmission line path. In other words benefits of shortest path vs easy access by road towards future servicing.
I lean towards path along road because wind and ice damage over the life of the line probably will more than offset the cost saved by shortest path, all just my guessed at opinion.

I also think that because the transmission line is going in, the path must have been already decided. With the decision of the transmission path they must also know that the road is also going in beside it. Ice road access is not likely to be adequate for servicing the line.