Note for those who confuse about Sukumvit Road. Sukumvit Road actually runs from Bangkok Sukumvit all the way to almost the Cambodia Border in Trad province. It is call "Tanon Sen Tang 3" "Road No. 3". Think it is the longest or second longest road in Thailand
Although I agree that Sukhumvit Rd is pretty long too. I drove back from Pattaya last month, along Sukhumvit Road and not the motorway, and stopped at Wang Mook (วังมุข). Nice seafood restaurant - lots of monkeys too.