Try signing in to your MCR first and then copy/paste the link:

mycokerewards.com/rewards/nantahala-river-whitewater-rafting-trip/28562WT.z_flt1=collection&WT.z_flt2=all&WT.z_flt3= all&WT.z_pclick=1&WT.z_flt4=all+Points&WT.ac=Regio n+SE_1_28562_7_32_c

If that doesn't work, then I guess it is a regional redemption....