The put in is by the Paradise Campground where White Cap Creek meets the Selway. Since the bank is steep there is a launch ramp to get gear down to the river. 

The drive to the put in is very long, but the road is either paved or dirt road in excellent condition so it isn't too bad.

From Darby Montana on US93, drive south until you reach the West Fork Road - it is just before a bridge over the Bitterroot River.  Head west, and then turn right onto the Nez Perce Pass Road.  Go over te pass to the Magurder Rnager Station and the Selway River.  Turn right to reach the Paradise Ranger Station.

Don't panic when the Selway looks like a creek when you first see it.  Many side streams increase the volume as you make your way towards Paradise, and White Cap Creek at Paradise effectively doubles the volume of the river.