That area is a fantastic place. I lived in Timmins for a while, and my father's side of the family is all from that area. It's actually where I started fly fishing.
Trout is incredibly hard to find info on up there (for good reason). In my time there, I only saw 2 small schools of brookies, and never landed any of them. I had heard a story of a nice brookie being landed in a certain river there (PM me and I can provide some details), but as this was my second time fly fishing, I came home empty handed (see photo below of the river I'm talking about - absolutely gorgeous!)
In terms of bass, pike, and walleye? This will depend on whether or not you have access to a boat. That being said, there is a RIDICULOUS amount of water to explore that way - easy to be overwhelmed and not know where to start. I would take what people tell you from forums, do some research, and really narrow down which waterways you want to try out.
The Mattagami River (the main river that flows through town) is host to many different species, and although I only caught smallies, I saw people in boats having more luck than I. There's an access point off of Airport Rd that is well kept and well known. There is also a generating station at one point, so be cautious.
The other main lake I hear about folks having luck with 'eyes are in Night Hawk Lake (the massive lake just east of town). A boat would be your best bet in this lake, although people commonly fish from shore by the bridge for walleye.
Not sure where you're staying, but if you can go a little further North to Cochrane, there is a lake North of town called Pierre Lake which was absolutely fantastic for pike and walleye (this being 5-6 years ago). As Millhouse mentioned, Chapleau is also a very good town to fish out of!
If you have any questions whatsoever about any waterways that way that aren't mentioned above, PM me - I still have a few good friends up that way, one of which is an avid canoer and knows the water up there very well - I'm sure he could tell me what's in a certain lake or river, and I certainly don't mind asking him.
Cheers,
Cody