Just how much gravel (aka crushed stone ) can my frame and wheels take!

I dropped my car at the dealer for service today, which meant I had to either walk my 1/2 mile lane in cycling shoes or ride the SOB. The whole way (besides being terrified of crashing especially on the steep descents, bouncing up and down so hard I could barely see and trying to use just enough rear brake) I was listening to rocks pinging off my bottom bracket, spokes and who knows what. I haven't even looked how many chips I put in the paint I don't really want to know.

(didn't crash though - although I did half-paddle my bike down the initial, 200 ft., 10% grade)