Discourse has the try.discourse.org forum as a place to see user features. Maybe you could create a parallel forum as a place to see admin features? Something like tryadmin.discourse.org
I understand you have a 14 day free trial, but at this stage I am just exploring one or two features at a time, very informally.
How do you imagine that working? An admin has access to everything, but maybe you wouldn’t like it if other testers had access to your email address and your IP address. In order to try things out, you would also have to be allowed to change things. How do you ensure that this isn’t exploited, for example, that no one installs a theme component that spies on others?