Does he sleep well at night? I would put the kabash on the rocking thing. It may be sweet at first, but if it becomes a habit, it will be painful to break. With my first child, I was very consistent with her naptimes and having her sleep in the crib. With my second, she just slept in the carseat, in the stroller, in her crib or wherever, whenever. I was usually running around with my first one to various activities and preschool and grocery shopping, etc. Most of the time, if she fell asleep in the car, I could transfer her to her crib without any fuss. With the infant carrier, I just let her sleep in the carseat, but when she switched to a big girl carseat, no can do.
Anyway, I guess my point is, If you are very consistent and let him cry for 15 minutes or so when you want him to nap, he will eventually do it (I used to set a timer for myself, to keep from going in and picking her up - she ALWAYS fell asleep before the buzzer went off!). If you want to go about living your life and just let him fall asleep whenever he can, that won't hurt him either.
My big thing was... as long as the child sleeps well at night, I just let the daytime work itself out. Everyone has natural rhythms, maybe you just have to figure out when he is naturally tired and have him nap then.
good luck!