How am I supposed to decorate a german chocolate cake if I don't use buttercream icing? Can I use the traditional nut/caramel icing between the layers then cover outside of cake with buttercream icing and my fondant accents? Will this taste ok?

Hmmm, that's a good question. I don't see why you couldn't do that. I would try to match the flavor of the bcf to either the german chocolate or the caramel. Just be sure to build a good dam around the edge of the layers so the nut/caramel icing doesn't ooze out. Would love to hear how it comes out!