One thing I think I saw last time maybe another concern. I saw you was using apple map for the navigation link. I believe it will work awesome on iPhone, but not on any other devices. So you may wanna find a better solution.

Some thing I found for your reference. 
http://habaneroconsulting.com/mobile/blog/posts/Opening_native_map_apps_from_the_mobile_browser.aspx#.UvkWIkJdWz4
http://stackoverflow.com/questions/12505745/need-new-method-for-linking-to-native-mapping-from-mobile-web-app