M.A.
i had the simular problem. but it was going from the crib to the bed and staying in it. it was hard because i put my kids to bed at 7pm every night no matter what. i would stop with the naps and suffer it out a couple of days. he is on a routine that you need to break the cycle. if he does not get a nap he will be tired and go to bed as early as you want it.
this does work because i have a 4,7,21 & 24 year old, and i will not let them control me. believe me i do know it works, you just have to be strong.