Matt,Here's a revised version of the code. The bike routes were added to the map as a DynamicMapServiceLayer. I also modified the extent so that the map opened zoomed into San Antonio. Since the basemap (World_Topo) is in Web Mercator (102100) I specified the San Antonio extent using coordinates that are valid for Web Mercator.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=7,IE=9" />
<!--The viewport meta tag is used to improve the presentation and behavior of the samples
on iOS devices-->
<meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no"/>
<title>
</title>
<link rel="stylesheet" type="text/css" href="http://serverapi.arcgisonline.com/jsapi/arcgis/2.5/js/dojo/dijit/themes/claro/claro.css">
<style type="text/css">
html, body { height: 100%; width: 100%; margin: 0; padding: 0; }
#map{
padding:0;
}
</style>
<script type="text/javascript">
var djConfig = {
parseOnLoad: true
};
</script>
<script type="text/javascript" src="http://serverapi.arcgisonline.com/jsapi/arcgis/?v=2.5"></script>
<script type="text/javascript">
dojo.require("dijit.dijit"); // optimize: load dijit layer
dojo.require("dijit.layout.BorderContainer");
dojo.require("dijit.layout.ContentPane");
dojo.require("esri.map");
dojo.require("esri.virtualearth.VETiledLayer");
dojo.require("dijit.TitlePane");
dojo.require("esri.dijit.BasemapGallery");
dojo.require("esri.arcgis.utils");
var map = null;
function init() {
var initExtent = new esri.geometry.Extent({"xmin":-11123269.230112463,"ymin":3379128.146430188,"xmax":-10804373.948106863,"ymax":3478190.535087729,"spatialReference":{"wkid":102100}});
map = new esri.Map("map",{extent:initExtent});
var initBasemap = new esri.layers.ArcGISTiledMapServiceLayer("http://server.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer");
map.addLayer(initBasemap);
var bikeRoutes = new esri.layers.ArcGISDynamicMapServiceLayer("https://gis.sanantonio.gov/ArcGIS/rest/services/BikeFacilities/MapServer");
map.addLayer(bikeRoutes);
createBasemapGallery();
//resize the map when the browser resizes
dojo.connect(dijit.byId('map'), 'resize', map,map.resize);
}
function createBasemapGallery() {
//add the basemap gallery, in this case we'll display maps from ArcGIS.com including bing maps
var basemapGallery = new esri.dijit.BasemapGallery({
showArcGISBasemaps: true,
bingMapsKey: 'Enter your Bing Maps Key',
map: map
}, "basemapGallery");
basemapGallery.startup();
dojo.connect(basemapGallery, "onError", function(msg) {console.log(msg)});
}
//show map on load
dojo.addOnLoad(init);
</script>
</head>
<body class="claro">
<div dojotype="dijit.layout.BorderContainer" design="headline" gutters="false" style="width:100%;height:100%;margin:0;">
<div id="map" dojotype="dijit.layout.ContentPane" region="center" style="border:1px solid #000;padding:0;">
<div style="position:absolute; right:20px; top:10px; z-Index:999;">
<div dojoType="dijit.TitlePane" title="Switch Basemap" closable="false" open="false">
<div dojoType="dijit.layout.ContentPane" style="width:380px; height:280px; overflow:auto;">
<div id="basemapGallery" ></div></div>
</div>
</div>
</div>
</div>
</body>
</html>