Jack, your comments are appreciated. After looking at things more closely I should be fine with "normal" through the wall routing of everything because the upper extent of the existing window area will fall within the correct plane for connections out the back of the inside unit, either left or right side, depending on how I decide to handle one other small thing. The existing electrical run is sized correctly for cable, so that's just a matter of re-termination/extension and conversion to 240v. Outside, the drain line will not be an issue at all. The only remaining challenge is to decide whether or not to "ground mount" the external unit or wall mount it on the outside of the new wall that fills in the window opening. The building at that point is partially below grade and putting it "in" a window well is not a permitted configuration. I can do off to the side, above or below the window area on a leveled area on the slope or wall mount directly below "on" the new window wall but above ground.
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The most expensive tool is the one you buy "cheaply" and often...