By land you can get into Mexico very easily. I go to Mexico a least 2 times per year and stay there for at least a week and come back to US but there are times that I cross the border very easily without too much questioning and there are times that they do make a big deal. It is to what type of officer you get at the time. I always tell them that I am a RSO. Now, once you are in Mexico you can travel to anyplace in Mexico