Motorcyclists taking on the Cannonball Endurance Run from Daytona, Florida to Tacoma Washington in September will have a Rocker in their ranks. Patrick Simmons of the Doobie Brothers will straddle a 1929 Harley JD for the more than 4,000 mile trek. His wife, Cris, is onboard, too. She'll be only slightly less retro on her 1934 Harley. The couples son, Pat Jr., who finsihed in the top 20 of riders taking the first Cannonball vintage motorcycle challenge four years ago, was diagnosed with testicular cancer last year but has responded well to treatment. The couple is doing the ride to raise money for Stand Up To Cancer.