Congratulations to your husband!
And relax. While the cat pee boots PROBABLY wouldn't be the best choice for this soirée, if it's a typical academic crowd, just about anything else could pass muster!
First, though, some questions:
1. Where will the event be held? Will be it catered on campus, in someone's home, or in a local restaurant?
2. How many people will be attending?
3. What is the formality level of your town in general?
4. How formal (or informal) do people tend to be around campus?
My husband's an academic, too, and I have also taught at the university and at our local college from time to time. I have actually attended an event exactly like this for him! In our city, I'd feel perfectly appropriate wearing any of the following to this type of event:
A not-too-sexy dress with a jacket or dressy cardi, to be removed or not, depending on heat. (This was my choice).
Dressy trousers with a blouse and jacket or dressy sweater and appropriate accessories.
A skirt-and-top combo that feels great, preferably with a jacket.
What I WOULDN'T wear, in my city, is a real over-the-top sexy cocktail type dress, or at least not one that I couldn't disguise a bit with a jacket. Where I live, this would seem like "trying too hard." Having said that, it would be good to find out more about this event if you can, because mores differ considerably from place to place.
As for makeup, if you feel best natural, go as natural as you can. No need for more than a bit of lip balm if that is all you usually wear!
Post some pics of your ideas so we can see!