Any additional thoughts?
One thing I've noted is that 650c tire selection is quite limited. There is a continental gatorskin that isn't a bad tire, but most of the high-end tires in that size are specifically for either TT bikes or kid's bikes, without good general riding tires.
24" or 26" MTB sizes are good sizes for the rougher riding. I'm not sure about drop bar "cross" or "gravel" bikes. There are some 650B bikes, but you'd probably be best with a 26" conversion.