My primary goal with this meal/technique is to cook the fish for dinner, not preserve it for longer time periods. As I did it above, it is primarily cooked by poaching, and the wood smoke ads flavour.
If I were trying to preserve it longer, I think I would rub salt on it, leave it to cure for a few hours, then attempt to smoke it.
If I were to try to add sugar or a rub of some sort, I think I would go with honey: it is something I would be packing anyway and it should stick fairly well to the outside of the fish. My concern would be burning the honey to the bottom of the inside of the pot and never getting it off.
I like cooking fish on the trail, but don't like carrying a frying pan, tin foil, oil, seasoning just for the trout, and I'd prefer not to have to make a campfire to cook the fish either. I also find boiled fish unexciting. I was hoping to find a quick, easy, hassle-free way of preparing trout without having to carry any additional equipment or seasoning, and this method seems to fit the bill.
I want to experiment with much less water, or even none at all, and lower temperatures to see if I can get more of a hot-smoke out of it.
The primarily limitation is the small size of my pot (900ml) won't allow for very good smoking/drying if I wanted to do more of a dry smoke.
Keep in mind that I still have never tried this poach/hot smoke method on the trail, only at home a few times.