Why would timing slip from basically one day to the next.
So, what's different today than it was a few days ago? More than likely cold and wetness. First I'd stick a charger on the battery. The jeep might turn over well, but have a dead or low voltage cell. Then pull the distributor cap and spray some WD40 in there to make sure it's dry, if you still have points gently file them smooth, but not enough to change the gap. Or, you can put a piece of emery cloth between the points, a couple gentle pulls will be enough. Sometimes a film will build up on the points degrading the contacts to the point where a weather change can cause starting problems. Stop there, put the cap back on. Spritz a little ether in the carb. and give her a try. I'd almost bet she will start. Could be water in the tank or fuel lines, dump some dry gas in the tank, if possible bring it into a heated environment to try starting. If your Jeep ran and started well a couple days ago what ever is wrong isn't serious. For goodness sake don't start a major tear down, this is weather related.