For the record, my cooling system problem was a blown water pump seal. The Daks have a history of problems with this part, but they usually seem to go around the 20K mile part. Since mine has 60K on it, and didn't show any trace of the problem until then, I thought it was OK. Wrong!
Skwerl's radiator did develop a leak, though, most likely from a rock strike.
And also for the record, here's a list of other things that went wrong with my bike during the trip.
Fork seals (both)-Yeah, I'm the one stupid and lazy enough to go without fork boots. I had replaced them about a month before the trip. No imperfections discovered on the fork tubes, but lotsa bugs smooshed themselves against my suspension parts on this trip.
Broken subframe mounting bolt (left side, lower mount)-discovered in my garage after a thorough washing. I guess that my subframe wasn't real fond of the thrashing I gave it. Hey JimC, how did yours look once you stripped off your bags, etc.?
And I started with a failed rear master cylinder (hence my trip to Big Sky BMW prior to the trip starting) and a bearing in my dogbone that had a little play in it. And I'm doing the 60K service this week. My BMW dealer really likes me (and my credit card) right now.