The river appears high right now (USGS link here), and I’d suggest waiting for the flows to go down. Personally, I like it when it’s 400 cfs and below.
This river heats up quickly, and so, I like to hit it before the summer sun really bakes it. Last year, I didn’t fish it much. The flows were very high for a while, and by the time they lowered, the water temp. already was really high.
There are some cold seeps coming from some of the banks, but they’re rare. I don’t like to take the chance and decide to leave the fish alone when things warm up.
FYI, our Millers online guide is here, complete with suggested spots and flies.
The river is a great DIY spot for stockies. I hope you get a chance to enjoy it.