Yep, I hear what your saying about packing butter/margarine along. Fresh herbs aren't too practical either I reckon.

When we used to backpack in and fish the Olympics over in Western Washington, we pan fried a lot of what we caught. Now for that you have to use at least a little oil of some sort, which was not a problem to pack along, and we also brought some eggs with us, so we could batter fry fresh caught trout for breakfast along with some pancakes. All we used on the trout was an egg wash with salt and pepper, and man was that some good grub. I reckon that Tony Chachere's cajun spice seasoning is about as versatile a seasoning as you could pack. If you don't like hot seasonings, just take some seasoning salt along instead. Generally speaking, if I am lake fishing, I will cook the fish well done, as they may contain more parasites than river fish, but that's just my experience.

Have fun.