i didn't read the rest of the posts so i am sorry if i repeat anything!
My now 15 mo old son ONLY napped in his swing (if we were home) and stroller of we were out. It got to the point where i bought a swing for my moms house so i wouldnt have to cart mine over!
Anyway... i let him do it until he started to turn over and sit on his own, i was afraid then he would turn out of the swing. I sleep trained him at 4 months, and once he was sleeping solid through the night it was easy to tackle the napping in the crib at around 6/ 7 months.
it worked after a few days... i know people tell you what is "good" and "bad" when raising kids, but I learned that if that is how I am going to get a break with him sleeping in the swing, it is not the end of the world! He wont be 18 and sleeping in the swing!!!
Let him nap there... he is too young to "train" anyway!!! YOu need the break especially with a 2 yo!!!