I personally feel that 2 hours is enough time if you don't dwaddle and don't have a ton of luggage, but you still do run the risk of the outbound flight being delayed. Are these two flights on the same PNR? If so, I'm guessing there are later flights to Tuscon that you can be reassigned on is it possible to see if you can get a later flight out of LAX to cushion your itin??