There are a number of ways you may keep your upper management informed without logging into Clarizen.
You may share the gantt chart, or the road map (optionally with the entire WBS) of your projects, via widget or email.
In our upcoming F3 you will have the ability to share views as widgets as well.
However, if your upper management wants full read access, then it would be beneficial for them to have a full license, as they will be able to have their own portfolio dashboard in clarizen, filterable and searchable, including chart views as well. They will also be able to drill down into projects, view financial data and documents.
Finally, for more advanced and customizable reports and dashboards for management, I would invite you to check out our excel add in http://www.clarizen.com/appsmarketplace/item/Clarizen-Excel-Add-in
I recommend to you to discuss with your customer success manager to determine the best solution for your company's use case