From the Res. upstream to the confluence of the N. and S. Forks of Silver creek you can keep two per day. Above the confluence, it's C&R. Downstream of the state park, there is a tiny bit of BLM land at the property line, but everything else is private land and a long ways from the road as well. Your only options are in the State park as far as the trails go, or at the Res.
Edit: There are dozens of access points around the campgrounds and road/ trail crossings. Just find a good, secluded deep run or hole where the fish haven't encountered people playing in the water.