San Carlos by afternoon should be doable if you cross the border early enough. Problem could be at the permit stop if many people get there before you. It being Christmas time there could still be "paisanos" (Mexican returning home for the holidays) crossing droves with truckloads of toys for boys and girls as well as all kinds of other stuff - refrigerators to kitchen sinks and everything else loaded to the gills. Maybe they have already passed by now. But if they are still streaming down there they can really jamb things up at check points. As I recall the border at Mariposa does not open early but not sure when. Try to check online - Border Wait Times - so you can be among the first to cross. Chances are the paisanos are already home with their families as we see them start crossing right after Thanksgiving. But if they are still out on the road it may take a while longer to get to San Carlos.
https://bwt.cbp.gov/index.html?com=1&pas=1&ped=1&plist=2604
