I definitely have a prefence for fishing the Ronde from Troy to Boggan's Oasis. Part of the reason for this is that it is road accessible, and the river from Boggan's down it primarily accessed by floating it. There are other reasons for my preference, the shear number of runs on the river, so many I can't imagine that they could all be named, and they can all hold fish. There don't really seem to secret spots on the Grande Ronde, you pioneer your own water and you may find fish, sometimes alot of them.
The Vistas and the wildlife that the Grande Ronde canyon present can be amazing. There are also numerous deer and Bighorn Sheep around the Ronde, as well as a great variety of birds. On my last trip I was fishing on of my favorite runs as night was setting in and from up the canyon wall, not far away, an owl began to hoot, it had a deep, low quality to the sound and sent shivers down my spine.
On my first trip to the Boggan's area I fished a 13'3" 7wt which was fine for the size of the river, but I would have preferred a lighter rod for the diminutive size of the fish, 4-6lbs on average. In my recent trips to the Ronde I have fished either an 8110-4 Sage switch rods which fishes much smaller than an 8wt and is alot of fun on smaller rivers, or a 6126-3 Sage, really this rod can do anything.
My best luck on the Grande Ronde has been on muddlers, Specifically a brown/pumpkin colored muddler, but my experience is very limited. On the first run I fished, on my first morning fishing the area around Boggan's Oasis. I landed three steelhead all on a brown muddler, so since then I have had a disproportionate level of confidence in this fly, and I have hooked fish on it.
There are several guides that work the Grande Ronde, such as Scott O'Donnoll, Ed Ward, and Mike McCune run Spey Water Guide Service, I know that John Farrar is also guiding the Ronde and has done so for a long time. I guess guides could be really good especially when fishing is tough and when a person wants to float the river, and I guess it is a great way to improve a persons spey/skagit casting techniques in a fun and fishy environment. I don't know that I would want to be guided on this river though, because to me the Ronde is a great river to pit your own skills against, as there are many classic runs on the river, all of which can hold fish, and there is an opportunity to find a good run on your own, on your own ability of reading the water and then going in and hooking a fish (if it all works out) it's kind of like matching the hatch without a guide for you trout guys.Not all my fishing partners are as in love with the Grande Ronde as I am. They like the river, but they have other rivers that trrump it in their minds and hearts. For me the Ronde is just what a Summer/Fall river should be. The fish are smaller, but they are grabby and a very long way from the Ocean. They capture my imagination with there long travels and my heart with their lively and aggressive natures.