If you head up Hwy 11 North of Barrie and a bit past Orillia you'll begin to find some sizable areas of Crown Land. There's a large swath of it on the West side of Sparrow Lake (accessable via railway lines) and probably from a couple of roads around the Matchedash Lake area to the south (it's just outside of the area covered by the Crown Land Atlas, and falls within the part of WMU 76 that has a rifled controlled hunt for deer in November and again in December. There should be lots of turkeys there as well, some bear, wolves, coyotes and small game like snowshoes, Ruffed Grouse and woodcock. Puddler ducks also frequent some of the beaver ponds, though a canoe or dog is necessary. Its a large area with its fair share of swamps and uneven terrain, so you'd really want to familiarize yourself with it, especially before deer season.
There's some further tracts of Crown Land Along the north side of the Severn River west of Sparrow Lake, plus some smaller plots in the area that may or may not be easy to access (some roads are maintained by the township while there's also several gated roads shared by cottagers). Further east but still west of Hwy 11, there's the Muldrew Lake Barrens (a bit hard to access) and several thousand acres of Crown Land East of Hwy 11 and North of Severn Bridge on the North and South sides of Kashe Lake, with at least a km of frontage with a public road on the more northerly tract. Most of these areas fall within WMU 46, which has a rifle season for deer, though you should be careful about that, since a bit to the north you run into a WMU that has a shotgun only season, an awfully ridiculous measure to appease cottagers from Toronto. Though I've seen and heard turkeys on several occassions, there's no season there yet. Grouse, snowshoe hare and woodcock can be had, though you need the special wolf/coyote tag to hunt those predators and are limited to two a season. Looking at the draw results, it should not be difficult to get tags for both the Controlled Hunt in WMU76 as well as the Antlerless Tag for WMU 46.
For waterfowl, there's Grass Lake just south of Sparrow and connected to the Severn Canal. Probably one's best bet would be to launch a small boat or canoe from a public launch located on the river and paddling down to the outlet of the lake which is separated from the canal by a railway. There's also some waterfowling to be had on Sparrow and Kashe Lakes, perhaps even several of the smaller ones like Morrison and Muldrew Lake, though you have to know where to hunt since much of the shoreline is dotted with cottages. Early in the season there's mostly wood duck, mallard, mergansers and geese, followed by ringneck ducks. Though I mostly heard about it from other hunters, decent numbers of diver ducks show up after Thanksgiving, when there's alot less cottagers, fishermen and recreation watercraft around. There's a mixture of bufflehead, goldeneye and bluebills right up to when the lakes freeze over.
As mentioned by others, there's opportunities further south, largely in the Simcoe County Forests, though many of them are smaller tracts of planted trees that vary in hunting potential. One larger tract of Land, the Copeland Forest just off Hwy 400 northwest of Barrie might be worth your time, as it's about one to two miles wide and severl miles long. There's small game, a few wetlands and a controlled muzzleloader hunt for deer in November. Waterfowl hunters can take advantage of the Wye Marsh near Midland, Matchedash Bay, and further south, at Luther Marsh just Northwest of Orangeville and the Holland Marsh just north of Brantford. These mostly require boats or canoes, though some small game hunting and limited shoreline hunting can be had at Luther, as well as shotgun hunting for deer. Luther used to be known as a madhouse years ago due to the huge numbers of hunters, many of whom got their licenses in the days before the Hunter Safety Course was mandatory, much less the PAL course. Time, as well as the advent of steel shot regulations has gotten rid of many of those hunters however, so it's sometimes possible to hunt with some reasonable degree of solitude, though it may take greater effort to get away from the crowds.
If you do some more research, you'll find that there's a few hunting areas west of Toronto (ie. Beverly Swamp) and some County Forests managed by the Grand River Conservation Authority that charge a nominal fee (about $40, plus OFAH Membership for insurance purposes), as well as running an annual pheasant hunt aroud Conestogo Lake. To the north east of Toronto, especially beyond Peterborough, you once again get into areas with large tracts of Crown Land, though you'd have to research that yourself or ask other hunters who know that area far better than I. If you continue eastwards along the 401, there's waterfowl Hunting at Presqu'ille Provincial Park and one or two public hunting areas (probably closer to two hours drive away however), and almost all of the land there is private.
I hope that gives you something to start with. I wish there was more and closer opportunities to hunt, but that still leaves you with an awfull lot of places with public access, and alot more than most people would expect to find so close to Toronto. If you have any further questions feel free to ask and I'll do my best to help.
Regards,
Frank