I have always used a 5 wt backpacking, just because of the wind and distance issue. Gotta agree with Shawn--I don't think it matters how fast a 3 wt is, in the wind, it is still a 3 wt.
I have never packed a spare rod into the wilderness. I would rather put the extra weight into food or drink

I haven't broken a rod backpacking, so I guess I have been lucky. I figure I can always rig something up if I broke my rod (I do know how to make a casting device from a tin can).
I like my St. Croix Imperial for backpacking--about $150.
Looking forward to the report. Is it summer yet?
Dawn