The Truckee River runs straight through downtown Reno, and the Truckee River Walk that follows its banks for several blocks is the single most pleasant outdoor stretch in central Reno. Cottonwoods overhang the water; benches, public art, and a few cafe terraces line the path; and at the Reno Whitewater Park near the Wingfield Park bandshell the city has engineered a series of pools and drops where kayakers, river-surfers, and on hot summer afternoons a steady stream of tubers float past the casinos.
You can hire a kayak, paddleboard, or river tube from outfitters just upstream and float through downtown in twenty minutes. Or just walk: from the Riverside hotel west to Idlewild Park and back is the classic out-and-back, an hour at a stroll.