Any cabin on Mariner is great (except maybe 1060 ;) ). I would never pay more than a Cat H. As for land side in Alaska, didn't find that it really mattered. You go in and out of channels and bays that you probably have an equal chance of seeing land on both sides. The day between Hubbard Glacier and Seward you are too far out to sea to have much of a view.

If I got to choose any cabin on Mariner, I would choose a Cat G (but only pay for H) around the rear stairwell. That stairwell is really convenient and is a "double wide" so it is easy to pass people. Of course, the Cat H are also good with access via casino stairwell to Stars Lounge and the Garden Promenade.