Noise is not an issue at all. We couldnt hear the people in rooms near us, much less DCA or DTD. We enjoyed out stay, but did feel the walk was a bit far for the price you pay. I wish they would start a shuttle or tram from there. And, yes, we did use the monorail and cut thru the GC. It was still a long walk with sleepy children after 15 hours in the park.
Back before DTD the parking tram ran from PP. I find it silly that they expect everyone to walk now that there is DTD, the enterance is still just as far from the hotel!