Myre-Big Island State Park, MN

Addy, we plan on hitting Minnesota the 28 of August and spending about two weeks in and around mid-state. I was really interested in the yearly pass, as a disabled veteran I was told I can receive a yearly pass for nothing. I could find no facilities online for such provisions. I was just hoping Myre-Big would have an office where I could talk to someone and show my credentials, as that would be the first MN park we plan to stop.
I guess I wait until Monday this week and try to call the park or someone for some advice.

thanks for the info.