My Ds naps in his swing. I have tried to get him to sleep in the crib or pack and play but there is too much going on with DD or the dog and he wakes up and I have to rock him back to sleep. In the swing he naps 2 hours sometimes. He also doesn't sleep well at night.
Re: where does or did your infant nap?
This may or may not be helpful to you but we have the munchkin white noise machine and love it. I didn't buy it until DS was about 7 months and I wished we had had it the whole time. It's pretty cheap and we haven't had any issues with it yet (I guess we've been using it for about 4 months almost all day and night). Here's a link to it on amazon:
https://www.amazon.com/Munchkin-Nursery-Projector-Sound-System/dp/B006SFUEF2/ref=sr_1_1?ie=UTF8&qid=1344635377&sr=8-1&keywords=munchkin+sound+machine
It comes with a projector, too but we never use that part of it. Good luck!
Mine goes back and forth between swing, RnP and PnP. The swing and RnP are in my bedroom, so usually away from noise. But he is often woken up.
Have you tried putting him in the swing to sleep at night? You may get a better night's sleep out of him that way.