M.B.
The best doctors for thyroid are usually general practitioners UNLESS you know that you have something very acute like thyroid cancer. But, if you are dealing with low or hyper thyroid function, most endocrinologist are not very useful, as they're trained to treat organ failure and not the very, very slow decline of thyroid function that many of us experience.
Your best bet is to join the Texas Thyroid Yahoo group where folks share experiences and can recommend doctors that folks on the list have had good luck with. AFAIK, there isn't one in your area and there are overall, very, very few good ones in this area. There are folks that have dealt with the whole range of thyroid issues in this group: http://health.groups.yahoo.com/group/Texas_Thyroid_Groups/
The majority of folks have gotten well using GOOD primary care physicians and those are quite rare these days.