After two days with friends in McAllen, TX, who are experienced in Mexican land travel, we crossed the border at Reynosa with no trouble. We had imported the car and gotten our visas ahead of time and we breezed through. In addition, we haven't been stopped at any check points. The importation sticker on our windshield must assure everyone that we are kosher, although we have a Wyoming license.
Our first night was in Tampico. We didn't tour anyplace except to visit the plazas, watch people, and requaint ourselves with Mexican beer.