You may find that it will die above the 'grey' stuff. I would prune any canes out that look like that. No point letting it put effort into a stem that will just limp along all summer. It will grow from a bud below the dead wood.

Also, Sunnyside, when you prune into the gray cane is the pith nice and fresh looking? Probably not, and if not, prune down til it is. As Caldonbeck points out, it will be a disappointing year if the cane just limps along. You'll have better bloom if you just get it over and prune it away. I can, however, empathize with the wish to leave all this long cane that seems bursting with life after our mild winter. It is so unusual to have to make so many decisions and one wonders what the garden could be if it was all left to keep growing...Ah, dreams of warmer zone rose gardening!

Maybe you could root the red stuff beyond the gray stuff after you cut it off the plant. That way it would not be wasted.

Rosefolly