If you have a car, it's worth the hour drive. Very popular in the summer time, it's hard to beat the lake with view of the Sawtooth Mountains in the backdrop. You can go to redfish lodge and relax with a drink at the marina or beach or go for a hike on one of the many trails around the lake
If you have some more time and are looking for a little longer, more strenuous hike, you can try the hike to Pioneer Cabin. It is an 8 mile round trip out and back trail with some pretty significant elevation gain. It can take several hours to complete, but you'll see some absolutely breathtaking views