85'/mile is 1.6% grade, not exactly a hill. A hill would be >200'/mile. Illinois around Chicago is pretty flat but not so much that
a 1.6% grade would be remarkable. If you are a spinner, the 36t cassette and 30t CW should be enough for 10% grades out to a
mile or so in length and shorter 15% grades of perhaps a few hundred yards. I find steering to be a problem below 4 mph.
100 rpm cadence in the gear you listed is about 6 mph.
Um, that figure of climbing per mile is averaged over the whole distance, including downhills and flat-ish sections.