advice on how to navigate suitelet pages?

I’m looking for guidance on the best way to handle the navigation of multi-page suitelets – how should the script handle each incoming page request and respond with the right page?

I’ve tried using session variables, which works but seems fragile – if you reload a page or use the browser’s back button you can get “That scriptlet is invalid, disabled, or no longer exists.”

Is there a way to append a “page name” parameter to urls, or add hidden fields, to identify which page the user needs?

Any basic tips much appreciated!
Thanks
Ben