First, a big thank you to all who commented and voted. Your observations are insightful and quite interesting! I invite folks to continue voting and commenting as thoughts occur.
I am glad that a couple of folks liked the "Minnesota Junction", as that feature took a ton of time to put together. I wanted these track sections to snap together tightly and without miss-alignment or internal stress or compression within the small internal space of the junction, so the connection tolerance for Minnesota Junction is 1/32" (with a lot of small fitter sections of track). I have worked on the Chippewa over multiple years, trying with O-36 and 12' and 14', but this attempt turnout out better. Here is a roughly 4.5' x 12' O-36 plan that is somewhat similar (with the elevated loop and grade flipped), which I actually constructed years ago (but did not get far with scenery):
A "Minnesota Junction" looks like it could be crafted into John's plan, if he should so desire (adding 4 more turnouts). Or the crossing eliminated as some have suggested (though I think it is a good feature). There are crossovers between the main lines at the top of John's plan so trains can move between the inside and outside routes without the crossing.
If John were interested, the 'N' gauge amusement ride loop could be replaced with a loop and more of elevated On30 track, for more bridges and scenic interest, but without the grade. Just an idea that could be explored.
As has been observed, the cool turntable fits tightly but is only 24", and some whisker tracks are short.
Of course the Chippewa could be stretched a bit to use more of John's space, if desired.
Both plans have the similar challenges with access and reach. Both plans could benefit from a yard and staging tracks for more trains, but not within the existing footprint.
Anyway, both are good plans with lots of interesting train running, switching, and scenic features, so it would seem to come down to personal preferences, and what John Armstrong would call one's "givens and druthers".