Simo attempted his first NASCAR Cup Series races in 2000 with Donlavey Racing. He raced the #90 Hills Brothers Coffee Ford to a 36th place finish and failed to qualify the #90 car at Watkins Glen. For the 2001 season, Simo again returned to run the road courses for Donlavey Racing. He earned a 15th place starting spot at Infineon, but unfortunately finished 42nd after transmission failure. At Watkins Glen, Simo qualified 42nd and ended up finishing the race in 37th after a crash. Simo did not return to the Sprint Cup Series until 2005 when he raced the #33 Korbel California Champagnes Chevrolet at Infineon. He started the race in 22nd and worked his way up to 10th place to finish the race with his first top ten. In 2006, Simo was selected to run the road course events for Front Row Motorsports. He was unable to qualify the #61 Chevrolet at Infineon, however he did qualify the #34 Chevrolet for Watkins Glen. Unfortunately, his race at Watkins Glen would end early with a crash and he finished in the 41st position. For 2007, Simo attempted both road courses for Front Row Motorsports in the #37 Dodge, however he was unable to qualify. In the 2008 season, Simo again drove for FRM in the #34 Ford at Infineon, finishing 43rd.