If you are interested in gardens, you could try checking out some photo slide shows of the past JH Garden tours (just happened last weekend so too late to go this year). Here is one tour that in most cases lists the names of the gardens in captions on the lower left side.
http://www.flickr.com/photos/judibean/5846721621/in/photostream/EDIT: better link
http://www.flickr.com/search/?w=9827685@N07&q=jackson%20heights%20gardenI happen to live in a garden-facing unit (towards the back, not towards the street) so my apartment is very quiet. I do still hear some traffic noise but it seems faint, except for some occasional honking and sirens. I would imagine if you are interested in quiet, that you would probably want to consider a garden facing unit instead of one that faces the street.
In terms of congestion, it seems to me that the '80s streets in the historic district are less congested than the ones in the '70s, but that's obviously a generalization. I have also noticed that the bus streets, which I believe are 74th, 75th, 81st, 82nd and 83rd ( someone please correct me if I am wrong) seem to have more honking due to buses not being able to get around people who are double parked.
I would also highly suggest working with a LOCAL realtor, or several local realtors, instead of non-local realtors, because they will have more knowledge of features of individual buildings.