Esri-Leaflet with feature service and clicky popup

Need to figure out:

How to not make this load so terribly
How to query and use the data from the related http://gis.gscplanning.com/arcgis/rest/services/Parcels/FeatureServer/0

<html>
<head>
	<meta charset=utf-8 />
	<title>Esri-Leaflet | Simple Feature Layer + Clicky!</title>
	<meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />

<link rel="stylesheet" href="//cdn.jsdelivr.net/leaflet/0.7.3/leaflet.css" />
	<script src="//cdn.jsdelivr.net/leaflet/0.7.3/leaflet.js"></script>

<script src="//cdn.jsdelivr.net/leaflet.esri/1.0.0/esri-leaflet.js"></script>

L.esri.basemapLayer('DarkGray').addTo(map);
		var parcels = L.esri.featureLayer({
			url: 'https://gis.gscplanning.com/arcgis/rest/services/Parcels/FeatureServer/0',
			style: ({
				color: 'red',
				weight: 1,
				fillOpacity: 0
			})
		}).addTo(map);

parcels.bindPopup(function (feature) {
			return L.Util.template('<p>{GIS_MapID}', feature.properties);
		});
		
	</script>
</body>
</html>

https://cdn.jsdelivr.net/leaflet/0.7.3/leaflet.js

https://cdn.jsdelivr.net/leaflet.esri/1.0.0/esri-leaflet.js