You're making me Nostalgic!
Damn . . it really is a small world! I used to fish the Madison with my dad years ago. In fact, I still have a couple tattered Madison River Fishing Co hats laying around somewhere and well remember the same thoughts and experiences as Skookum expressed the first time I fished it.
We arrived there one late August evening and, after depositing our gear at the rental cabin and having dinner, I got the urge to check out the water. Since my dad wasn't much interested in anything but a little relaxation after hours of driving, I grabbed my cousin and we headed down to the river.
We drove south from Ennis and parked in the first boatlaunch/campground we found. Wading right down the middle of the river fishing the troughs along either bank, we marveled that we were able to do this.
I didn't know what flies might work (the first choice - a #10 Stimulator -failed miserably), but i'd been doing a lot of summer steelheading in Washington and decided that one of my favorites - a #6 peacock wolley bugger- might look good to a Montana trout. And I fished it just like I would for steelhead - cast it tight to shore, a big backmend, and a slow cross-current wet fly swing thru the trough.
I'd just reached some big concrete pillars in the streambed - looked to be remains of a washed out bridge - and was fishing along the soutern grassy bank - when the big rainbow clamped down on the bugger. My cousin, who was used to Arkansas trout in the 10" range, was screaming advice at me as the trout raced back and forth in the riffle between us.
After a splashy landing on a shallow weedy island in the middle of the river, we both marvelled at the deep-bodied 22" rainbow. It was amazingly proportioned, with a hugh head and heavy body in front of the dorsal, then a much smaller posterior and tail. Looked like a piscatorial Arnold Schwarznegger! It was getting dark by then, so a quick picture and release and we were headed back to town.
The next morning we went into the MRFC and they showed us the rabbit strip leeches and other flies used to entice the big browns. And we floated with one of their guides that same day and got into some of those big browns as well as a couple nice rainbows. It was a memorable trip, and the Madison a great trout river.
I was just back to visit a friend last summer - that town has really grown in the past few years!