It an't flat where I am now.
It was back in Illinois where I bought my MB GR in 4/1972, lived & rode there until 11/2013. The stock 52/42f 14/24r was fine there for pretty much anything I encountered riding in NE Illinois.
Never made it out to around Galena though, that's a lot like where I am now.
So when I got back on the saddle earlier this year it became obvious to me the gearing had to change. Took awhile to find the stuff that's on it now, ready for the season when it warms up a bit next April: 52/47/37 front, 14/30 in back. The hills are still a challenge yet in what little test-riding I've done I've not felt so 'beaten up' by the grades as with the original 10 speeds.