I ran a Yellow Pages search, and found this business in Houston. (They're even a Rancho distributor).
Off-Road Unlimited Incorporated http://offroad-unlimited.net/
Local customer reviews?
http://local.yahoo.com/info-19072436...orated-houston
Maybe you could email them in advance and ask for recommendations for your situation? They might be able to suggest an alternative gauge and have it in stock when you get to Houston.