We were visiting relatives in the area and thought staying in a fort overnight would be fun for our boys, ages 5 & 7; so, I made reservations over the phone (open daily ~9-4:45). It's located about a mile south of Goliad (grocery store, etc). [There is a "gift shop" outside the fort but it is not affiliated w/the Presidio La Bahia].
Upon arrival at 2PM, check-in was delayed because the room wasn't cleaned and the credit card machine was malfunctioning. Someone else was called in to help promptly, but we had to carry our youngest (who wasn't feeling well) through the museum for a while. We walked around the stone fort to see the corner look-out points and a cannon, middle grounds and the chapel (note:public services held Sundays at 5PM). We were told they "forgot" we were coming (even though it was written in the calendar at the desk).
"The Quarters" (old soldier's quarters) was great for our family of 4! Two twin beds in one room and a queen bed in another, living room w/table and couch, fireplace (bring wood), bathroom w/shower, kitchen (w/fridge, stove-but no microwave, coffee maker (bring coffee), pots, plates, glasses, utensils...). It was clean and had central air/heat and plenty of sockets for electrical devices (for playing/recharging) since there is no TV.
At night, we went exploring & "ghost hunting" (supposed to be haunted by the soldiers who died there) and were disappointed to be locked out of the main grounds and confined to just the corner by the chapel (?maybe we misunderstood). We walked the perimeter w/flashlights and enjoyed lots of stars in the sky. The next morning, we cooked breakfast and took hot showers. However, when turning in the key, was again told they "forgot" to leave the gate unlocked for us. Expected more for $200/night!
May stay again? but would call ahead to make sure the room is ready and check the gate before the museum closes!

Staying at the Quarters at Presidio La Bahia is a one of a kind experience - if you are looking for no television, internet, or phone - if you want to feel like you have fallen through a hole in time for a day or two, you will not be disappointed. When the Fort closes for the day, you can still enter and wander the grounds through your room, and it is an amazing experience to have such a beautiful and peaceful place all to yourself.
There is a full fridge/freezer, stove and coffeemaker. (no microwave). They provide a coffeemaker and filters, but no coffee, so you will want to bring your own coffee and whatever you take in it. Stopping by a bakery on your way makes you able to enjoy coffee and breakfast on the grounds before it opens for the day to tourists - again, unbelievably peaceful and quiet. The town of Goliad is very interesting as well - it is picking up as a little touristy shopping district, and a wonderful little art cafe called Panache has recently opened on the courthouse square.

They rent the old priest quarters, and you get access to the Presidio grounds all night. The quarters are basically a two bedroom apartment, one large bed on one room, and two twins in the other. One bathroom with a shower, a kitchenette kind of kitchen, and rock walls. Perhaps because this is the location of the Massacre of Goliad, there are many ghost sightings reported at this location.
We filmed our visit to La Bahia, and it was quite interesting, as the person on duty told us of her personal sightings. See the videos and details at http://www.sailingtexas.com/TexasStateParks/Goliad/presidiolabahia.html

David