For an outdoor wedding you could try Anne Marie Gardens, or even the pagoda at Solomons.
I'm not sure if it's a religious ceremony or not, but one of the most beautiful churches in Calvert County is right on Broome's Island road near the CSM building.
For that small a crowd, you should have an easy time doing a reception. Depending on the money situation, you could book out a restaurant.....or to keep it out doors you could even have a tent set up and hire a nice caterer.