Big Bend is a great place to learn how to use a topo map. Unlike the mountains in CO, you will find good vistas of prominent land marks just about everywhere you go in the park. Get yourself a cheap compass which has the degrees mark on it. Get the National Geographic topo park map from the visitors center. When you stop for a rest on one of the well marked trails, get out the map and learn how to READ the topo lines to see where you are and what is around you. Once you find your location of the map, use the compass and figure out how the degrees/direction on the compass compare with the map and what you are looking at. Learn to use the topo and compass when you KNOW where you are.
And I agree, it is too late to think about new boots. Take an extra pair of socks on each hike and put them on at the turn around point to keep your feet dry and fresh feeling. Tape a few turns of duct tape around your water bottle so that you have it with you. You can use it to cover up any hot spots that develop on your feet.
