HSlogger, thanks for the response.
We tried to get the 3" minus but the person at the gravel pit told us that theirs had a lot of fines in it at the moment. So, my neighbor, who is an excavator, stated that we could use the cobble and top it off with crusher run. It was a bit of an emergency to get it done. But I know,from reading many posts here, is to use the chunky rock (3 " minus) with edges as a base and top with smaller material ( crusher run or 3/4 minus) so it locks together. This road is temporarily for vehicles and then will only be used by quads and tractors occasionally. I was hoping that whatever water doesn't make it into the pipe can travel through the cobble to the low side without washing out the road. It is not a river of water but a slow steady trickle coming down the hillside underground during wet times.