If you remember to bring your passport with you, then you can walk over the nearby rainbow bridge to see the falls from the Canadian side (arguably the better view of the falls). While on the American side, make sure to walk to goat island and the three sisters islands for the best views. There are also plentiful nature trails along the rapids and the upper falls. Don't forget to bring a jacket! The mist off the falls can get cold and, even though it is April, we can't promise it won't be icy.
For those of you with a passport and extra time, the nearby Canadian town of Niagara on the Lake is worth the drive. Full of cute shops and English bakeries, Niagara on the Lake is also great spot to grab a bottle of wine from one of the many Niagara Region wineries. Budget at least a few hours to wander in and out of storefronts and make it down to the public park by the river.
The Elmwood Village is a great spot to pop in and out of cute cafes and local shops. Check out the local bookshop and coffee house, Talking Leaves, or some of the many art studios along the main drag.