Just south of Goliad State Park is Presidio La Bahia. You can walk here from Goliad State park or make the short drive. I should warn that the hill from the road to the Presidio is a little steep and may be difficult for some. Driving may be best if you are unsure or with little ones.
From TPWD:
Located 1/4 mile south of Goliad State Park on U.S. Highway 183 and 77A and operated by the Catholic Diocese of Victoria. View exhibits, enjoy an interpretive program and exciting reenactments, and imagine life at the fort. Originally built in 1749 to protect the mission and the frontier, it later played a major role in the Texas Revolution. Here, Colonel Fannin and his ill-fated men were held prior to being executed at Santa Anna’s order, an act of infamy later recalled at the Battle of San Jacinto with the cry, “Remember Goliad! Remember the Alamo!” For a very special experience, make reservations to stay overnight in the comfortable Priests Quarters.
The Presidio is the origin of one of my favorite Texas Battle Flags. My friends and I still fly this one at tailgates and other events when we need to stand out in the crowd of flags.
Exploring Texas State Parks 