After trying it out more and more, I see how it works and is pretty smart. I decided to use the [at] and X-Map-Viewport options. When I get results back, I run them through this JS method. to compare the lat/lon of the Place with the bounds of my map. If it returns TRUE, I include it on the map as a result.
Code:
// Using a MapQuest map, so that's why the bounds object is different than a Nokia object.
function gp_latLngInBounds(lat,lng,bounds){
var minLat = bounds.lr.lat;
var maxLat = bounds.ul.lat;
var minLng = bounds.ul.lng;
var maxLng = bounds.lr.lng;
if(lat < minLat) { return false; }
if(lat > maxLat) { return false; }
if (minLng <= maxLng){
if(lng < minLng) { return false; }
if(lng > maxLng) { return false; }
} else {
if (lng > maxLng && lng < minLng) { return false; }
}
return true;
}