Without dogs, you are going to have to get EXTREMELY lucky. You can put in lots of miles and glass for crows or ravens on a kill. If you can find a fresh kill, you will know that a lion is at least in the area and then you can do some calling. If kill is really fresh, you can sit on the kill in hopes that the lion returns.
I am planning to leave Thursday for AZ and hunt them with hounds. Of all the hunting that I do, this is my favorite. Good luck.