Royal York is a decent hotel and very centrally located in downtown. Everything is walking distance. Other hotels you can try are Marriott Eaton Centre(next to famous Eaton Centre), Hilton Toronto(Richmond St), and Sheraton Centre(queen St).
If you like beaches Wasaga beach is one of the big beaches in the area with nice clean water.
They usually have the world competition of fireworks around this time.(not to be missed)

More event sand attractions and you can get info on city at www.toronto.com

Enjoy! the beautiful city.