The Ipsut Creek Road was once driveable its entire 5 miles, with the Ipsut Creek campground a drive in akin to Cougar Rock or Ohanapecosh. After two major flooding events the road has been converted to trail status, open to hiking and biking. This video was recorded on April 29, 2012. As of this writing (June, 2016) the trail has suffered more damage and some parts will be more difficult to transit on bike.
5 years later with mother nature keeping things in flux, this update (filmed on May 26, 2017) shows the entire trail with no time editing......23 minutes to cover the entire 5 miles.
This short video highlights some of the biking opportunities at Mt. Rainier National Park.