I fished the Eel a few years back. after a few days of getting skunked. we finished up the last day of our trip checking out and fishing the Trinity. We didn't get any sort of sign of steelhead, but it was a pretty river. Here are a few pictures of the river.
The Trinity flows from the Cascade mountains into the Klamath River and then to the Pacific. It seems to be a popular river for fising nymph and egg patterns. It is very clear water, at least when I saw it.