One of my fav memories of my first summer biking in Queens was going out on the Vanderbilt Pkwy, then after cutting north, getting completely, and I mean completely lost in that little forest. Thank god for a GPS phone. LOL. Then rode up along the Little Neck bay bike path. Wide, relaxed, fairly scenic for NYC. Looped down through Flushing on the way back, a diff kind of urban scenery :-) Could easily extend a route through Kissena / Flushing Meadow / Forest Parks and see a lot of cool stuff. Or keep going through Corona (stop by Louis Armstrong's house) towards Jackson Heights & Woodside.
Not much in central Qns though... A few weird back alleys or old houses that used to be farms (Onderdonk) near Bushwick & Ridgewood.