Houston covers a lot of area. I stayed at a Harris County Park on the Northwest side of Houston just north of the city of Tomball. A very nice county park that has 8, 90 degree, level, concrete pads with full hookup. The best price in the area -- Free-- with a 7 night limit. If you go to www.irv2.com
and at the top of the start page click on "campgrounds" and then scroll down to Texas, about the 3rd item down from the top look for Spring Creek Park. I posted pictures and contact information for you to make a reservation, I was there the first week of April. Reservations are not required but would be best that you make them.
The park is fairly large and pretty busy with outside activities on weekends. Paved streets, basketball courts, walking/biking trails, picnic pavillion. Restrooms with showers just across the street from the RV parking area. One caution, make sure you have a 20' sewer hose, 10' won't do it. Water hook up may also be a stretch depending on where the city water hook up is on your 5er as electric and water are at the rear of the pad rather than side. There is plenty of room for slides. Picnic tables, BBQ grills nearby. No swimming pool. It is patrolled by park personnel and the sheriff. It is in the big city so don't leave anything outside when you are gone that you want to keep. It's not a high crime area but don't tempt anyone since it is open to the public. Other RVrs keep an eye on what's going on.
A minimart is about 1/10th mile from the gate, shopping, restaurants, groceries in Tomball about 2 miles away. They do lock it up at 10:00pm and open back up at 6:00am and unless there is a 911 emergency you don't go in or out.
I will definitely go there again, but then, my daughter lives about 6 miles from there.