Depends on whether you want lower floor or upper floor, stairs or elevator, or if you want to face the Hippy Dippy Pool. If you want lower floor you can simply request "lower floor closer to Classic Hall". Then you could take the stairs close to Classic Hall. Otherwise, if you want upper floor and expect to use the elevator I don't think it matters much. For instance, you could be close to Classic Hall (i.e. coffee!!!!)

but on the 4th floor ... by the time you walk to the elevator in the middle of the building you've walked the same distance as if you were at the opposite end of the building.
I was there in January and stayed in #6458 a 4th floor lakefront view in the 70's.
Let's have some more experienced hands than I weigh in on this one.