In short - yes you can do this. Phonegap simply uses a large webview and loads local HTML. No reason why it couldn't point to a remote ASP page. However one of the great things about Apps is their offline capability ( speed of loading assets etc )
I would recommend making much of your App work with local stuff and possibly iFraming you remote pages. ( or even better write data services to call remotely with AJAX and render everything via local html )
remember , its an App , you don't want the user to experience "loading" straight away. If possible give them something to use without network and try your best to not make it feel just like a "shelled website"