Based on the personal “descriptives” and the type of riding you intend to do, I think that a vintage, classic, steel framed bike will suit you well. As mentioned, frame size will be important! Also as mentioned, group set brand won’t make too much difference. While indexed shifting systems are very nice, for the type of riding you described, friction systems will work well too. I have bikes with index shifters that I often put in the friction mode as I find myself not shifting with every slight change of terrain and friction shifters allow for precise “trimming” (which isn’t always the case with the early index systems).
With your mention of office buds that just may be bike snobs, you may wish to gravitate to the higher end of the classic brands. Raleigh, Bianchi, Miyata etc., all had product lines that spanned the full range of price points. Do your research! I’m sure you’ll find a nice classic ride
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