My dogs need to run

I know this is an odd request, but I actually feel desperate. My dog's really need to run leash-free. My back isn't good enough to walk them at a decent pace at all. One is a bully dog and even though he's not vicious, the dog-park just doesn't work for us.

We've been going to a neighborhood school for years that has been perfect. All fenced in, no potential for others dogs or people (I go at odd times) and plenty of grass. Well, the school started locking its gate and my dogs are devastated.

Does anybody know of any big grassy area that's hopefully at least mostly fenced in. I'm near the Heights in 77022. Even a business park that I could go to afterhours if it's safe enough from the streets. I would even be willing to do some sort of work, if needed, while I was there.

My dogs are 10 and taking away their free-run time at this point in their lives is breaking my heart. Like I said, I know it's an odd request and unlikely. But does anybody know any place at all near me? THANK YOU!