Actually I figured out how to do it by using the plugin contact-form-7-dynamic-text-extension and adding the desired text. I can have it on the page as text and then this will be sent so it shows up in the email.
[dynamichidden dynamichidden-826 “EATON CANYON VISITOR PERMIT ? A permit is required to enter Eaton Canyon”]
Now I just need to get the CAPTCHA to work…