When we could not find the trail due to visibility or buried cairns and signs we used a combination of a tyvek map and the GPS. The map has contour lines that were very useful and the map also shows which direction the trail heads (left, right, etc.) The GPS gave us waypoints that were extremely helpful in giving us a general direction. Some of it is guessing but with a map, compass, and GPS you can make an educated guess. We are looking into a new GPS and they actually have the topo maps that you can download into the unit. The cool part about that is you can always have a way to know exactly how far from the trail you are.
Our disaster plan was to locate a somewhat sheltered area and set up camp there to wait out the storms. We had enough rations for 3 full days and extra snacks. We only used 1 full day of rations on our trip and were capable of spending more days out there if we needed to.
Before heading out to do any adventure it is important to do your research before you go. We read books, maps, trip reports, talk with guides or other people who have experience, come up with disaster plans, and write down exact quantities of food for each person for each day, clothing, and supplies. We pack well before the trip and weigh our packs, do a quick run-through of setting up the tent (with gloves is helpful), test the stove and fuel setup, and try to pick several potential camping areas. When you need to move quickly being prepared in advance makes your trip more enjoyable and a lot safer.