Biggest factor I have seen for good quail success if providing diversity in a small area. A covey of quail calls about 40-50 acres of land home. If you can provide a good food source, cover, water and nesting area all in a small area. The quail will thrive.
They have done studies showing that even on quail populations that are just hanging on, hunting pressure really doesn't affect them. Hunters will rarely kill enough birds to bring them below the number that would be taken out by winter weather and other predators. If I owned land and had small numbers of quail on it, I think I'd be in your shoes too and not allow hunting or very light pressure at most. Quail can rebound quickly under the right conditions though.
