Thanks for the input. To answer some of the comments above, I have been there before, but I can't say I know the area. No, I don't work at the monastery, but I go there on retreat a couple of times a year (very nice place, good food, and reasonable cost; great place for rest and refreshment). "Multimodal" means taking a cab; there is nothing else. That's what I've done in the past, but since I wasn't driving, I never paid any attention tothe road. to the road. I don't really remember how much traffic there was, but I do remember it moving pretty fast, now that I think about it. All I know about the road conditions is what I can see in Street View on Google Maps. I'm now very comfortable dodging traffic, merging, taking the lane, etc. in city traffic going 20 or 30 mph, but 50+ with no way off the road seems like a different ball game, which I haven't really experienced.

A more experience friend came up with this route:

http://ridewithgps.com/routes/1947332

It's much longer (and pretty hilly at least for me on my 3 speed Brompton), but it avoids almost all of 9W. He also suggested taking a cab going up, and the next day ride around the area. Then I can decide whether I want to ride to the train station on the way back. That seems sensible. Or I could just take the plunge and ride to the monastery. This route could be work, but it doesn't look too risky. And we have to see what the weather looks like. That could moot the whole project.