Through the 2013 season, Jimmie Johnson has 39DNF's during his Cup Series career.
The NASCAR driver with the most DNFs (did not finish) is Dave Blaney. Richard Petty is another driver with a lot of incomplete races.
Yes, Bill Lester raced in the Truck Series. There is also Derek Strong, former NBA player for L.A. Lakers, L.A. Clippers and Orlando Magic, among others. Derek Strong is the only NBA player to successfully transition into stock car racing as a driver. He is part owner of his team, Strong Racing. Don't forget Marc Davis who drives Nationwide races.