I will definitely check the boards over. I can see there is little to no checking on the ends and boards seem to be stacked well -- owner claims they are straight and mostly clear. I will look for signs of bugs. These are 20" wide boards and none are live edge, so I don't envision there being much sapwood. Not sure if I'll be able to get much an idea on grain figure with old rough boards like this, but if they are bug free I'm pretty sure I'll take them. At under $5 per bd ft, its less than half what my lumber yard charges so I should come out ahead even if there's some waste.
John, any good resources for building with allowances for movement? I'd like to learn more.