Are you planning on camping on the Canadian side? If so, I would go online and check out campsite availability.
There is a lot to do on the Canadian side, sorry to say I have not visited the American side.
Marine land, Fort Erie, Busy downtown Lundy's Lane with museums, arcades, etc. Casino, Helicopter ride over falls. You can walk under the horseshoe falls, whirlpool rafting. Shopping. Wine tours, there are lots of vineyards. There are quite a few market gardens. Fresh peaches, grapes, nectarines etc. Also not far is Niagra on the Lake, very pretty town with beautiful gardens, shopping, theatre.
Have a great time.