Easy as pie. This setup used to be called voice lite, but what it sounds like you're looking for is a visual voicemail solution only. Download the app, during the setup select to never call using google voice, and complete the setup. If not given the option during setup you'll want to enable conditional call forwarding which only sends calls to VM when busy or no answer, open the dialer app on the phone and dial (for VzW i think its) *71 with your 10 digit GV number. Also if you werent prompted during the app setup, in the dialer hit menu, settings, and change the VM provider to google voice.
If done correctly, all voicemails will be handled through google voice and you can play them in any order, with text transcripts, from inside the GV app or via a computer browser.