Elora Gorge rapids fishing is awesome for brown trout. The scenery is amazing down there and if you do plan on fishing I would suggest early morning before all the water rafters comes crashing down the river. There are rules there as well. Catch and release, barbless hooks and no live baits. You will also catch small mouth bass and pike there as well.
West Montrose down river to Kitchener has some nice spots but I wouldn't waste my time unless you plan on taking a canoe down the river. The Grand river by hidden valley down towards Conestoga college produces some nice small mouth bass and pike as well. I usually wader down this stretch. Upper stretches of Conestoga river by the dam and down where Conestoga meets the Grand river has some really nice pools. You will catch bass, pike, walleye. I would suggest taking a canoe to cover that stretch of river. If you cannot take a canoe there are some access points but mostly all private land.