You are all so helpful! Thank You!!
And Carrie, thanks for reminding me of Sheldon Brown's article, which I am going to read tonight.
I live in a little town that is a lot like Mayberry, and if I put a giant U-lock on it I think I'd get laughed out of town. Many people don't even lock their houses when they go away on vacation around here.
But... it being a Rivendell and a nicer bike than in my wildest dreams for MY lifetime, and being that I learned "street smarts" the hard way as a kid in the streets of NYC, I feel I should at least cable it to a tree while I'm inside the bank or buying bread at the bakery. There are no street signs or even parking signs to lock it to around here, Main street is one block long and there is one traffic light in the whole town. Just a few trees and a couple of stair railings in front of stores, but I can cable it to those I think. I do worry about owners letting their dogs water a tree while my bike is there!

I won't be on my bike in any city environments, pretty much all rural, so I think a long cable will be the most logical choice to secure my bike to odd fixed objects of wildly varying diameter. I don't think there are many thieves with cable cutters roving the countryside here. Mostly I fear some mixed up teenager or troubled young man from a neighboring area seeing my bike leaning against a storefront temptingly, and impulsively deciding to jump on and ride away home with a nifty new bike for himself.

I'm still undecided as to combination vs key lock. I tend to remember combinations AND not lose keys. I guess I'll see what they have in stock at Harris' when I go to pick up my Beauty tomorrow. Will post about my experiences tomorrow evening when I get home.

I so much appreciate all your suggestions!