Playpark in town is kind of meh at these flows. But it will get you wet and there are usually some cute girls sun-bathing.
Alberton gorge is within 1/2 hour. The whitewater reminded me of westwater but easier. Cool geology but you won't have the place to yourself. Bring the playboat but don't expect to be blown away by the features. Warm water and drunken wal-mart rafters. There is a kayak take-out the cuts out flatwater at the end. Most kayakers put-in at 3 bridges but they miss the two best rapids IMHO, but again it adds flatwater and there isn't much in the way of play up top.
On the way to/from you could hit Alpine Canyon near Jackson, Gallatin and Beartrap Canyon near Bozeman.
The sunshine walked beside her