Texas requires a TxDot “charlie” number to operate intrastate. No UsDot needed. No Ifta. No federal inspection. Just state vehicle inspection on power unit and trailer. $35 a year “token” tag for trailers. Not sure on the port thing here. I know a few guys that run out of the Port of Houston to EL Peso, Lardredo, and the Valley and never leave the state. I never asked them how they self certified their license.