Oh my God, Joe, what a terrible story!
For the first 2000 miles of my ride, from New York City to Fort Collins, Colorado, I used a very thick chain kryptonite lock — the same one I use to keep my bike safe in New York City. It was heavy as hell; not 10 pounds, but probably five. That said, I also rarely let my bike or my panniers out of my sight during this period. If I went to eat in a restaurant I sat where I could see my locked up bike and panniers. When camping, the panniers were in my tent with me and my bike chained usually to the metal part of a park bench. If I stayed in a motel everything was in the room with me, including the bike.
Once I got to Colorado, the campgrounds I began to stay at were sufficiently isolated that I was (perhaps unrealistically?) less worried about bike theft — whereas I was now facing serious mountain climbing, so weight became a dominant concern. So I bought a much lighter cable lock, used it instead, and shipped my big thick kryptonite lock home.
Fingers crossed I’ve been lucky so far ….