I have not fished E Branch of Mahoning but I think I can put you on some information. Here are a couple of links that I'm hopeful will help you gain insight on where you should target for access. From the looks of things, there is a Special Regs section on that stream. Special Regs areas *should* be indicated with signs. Though I have fished a few sections of the ANF where signs seem to have been removed, possibly by anglers frustrated with those regulations. That of course is speculation. There's a nice Special Regs stretch below the Resivoir on the East Branch of Clarion River but that's in Elk County. Worth fishing if you are up in that area. That will also put you within a stone's throw of a few other special regs sections of stream.
This link will guide you to the stocking list, select Jefferson Co. and you will get a list of all stocked streams. Note they provide you with Latitude & Longitude of the stocked sections.
PFBC Trout Stocking
This link will give you a map of all of the streams by County in PA.
PFBC County Guide
It would be great to get an update once you're able to fish the stream. Feel free to shoot me a PM or post in the thread if you prefer.