There is an event here in Oregon called "Cycle Oregon". It is not so much a race as a planed and organized outing for something over 1000 souls on bikes. The bike riders pay to participate and meals and rest break amenities are provided. They do put up signs along the route warning motorists. I don't know how many days the event lasts. 3 or 4 I guess. They have come through our area several different years. The bike riders are considerate enough, but it is imposible with that many bikes on the highways that traffic will not be backed up and some motorists will try to pass bikers out of frustration at locations where they really shouldn't. I don't think the bikers add much to the economy as the catering comes with them from far off and they really don't shop while they are in the area. Where would they put something if they bought it. I can't say as I care much for the event comming through my area.
Dan: when I was a kid they used to drive cattle through Enterprise like you mention in John Day. I think this was back when UP still maintained a stock yard here and the cattle were destined to take a train ride. But in any event, try getting your vehicle through a herd of sheep on the road that is being driven the same direction you want to go. It's way worse than cows!