I did some research here. Turns out that cipro does, well, absolutely nothing for giardia. The layover did help, but it was probably the rest. I do have a bottle of furazolidone, which is the actual giardia treatment. But. I was silly and sent it in my bounce box to Kennedy Meadows, which is another 150 miles north o' here.
So ... er. If anyone is within driving distance of Mojave, and is willing to do me a biiiiiig favor, please give (530) 798-3922 a call and leave me a message. I'll check voicemail later tonight. And I'll probably be laid over in Mojave a day or two in any case.
The good news is, Imodium at least controls the primary symptom (the diarrhea) pretty well. The fatigue is getting to me off and on, but I've made some progress in the meantime -- another 100 miles down, and the worst stretch of desert is now behind me. More details in a phone post later, unless I can find an internet cafe.