Thanks all for your helpful thoughts. Just to report back, I only really got one morning to explore the rivers, the rest was keeping the rug rats from getting sun burned and bite by rattle snakes. We ended up finding a beautiful spot on the Methow, downstream from Winthrop. The main stem was raging, unfishable. This spot was the thin side of a large island that held half a dozen snags with great looking holes. My buddy fished streamers with no luck. I ended up with one white fish and one rainbow, both very nice size, and both on the stonefly rubber leg nymph. Saw a few other rises to our flies, but all in all, a pretty quiet morning over beautiful water. Didn't get to fish the Chewuch, but that looked a bit more manageable, but didn't see obvious access between town and the turnoff to the park. BTW, if you do ever camp at Pearrygin, opt for the second camp ground. It's much nicer, more space, newer amenities and quieter.
We did fish the lake and brought a few in from both the dock and on float tube, but it was a bit frustrating. The fish were rising for hours, and folks fishing powerbait were bringing them in chilly willy style. I tried every fly in my box, but could only fool a random few. It was great for the kids though, as we ended up throwing PB so the kids didn't think we were just bluffing. All in all, a great family camping trip, but didn't have the fly fishing mojo this time.
