I used to live in nor cal and when it comes to hunting those darn black tails in ca you should also try to find thier water source. Even if their water is just a small spring there should be plenty of sign. I have hunted in years past and had 100 degree weather in mid oct.

The other thing to with the trails is you need to know also if there are thier normal food/water/bed trails or if that there escape route when they feel presure.

If the area does not have too much presure its problay a food trail. if the area has a lot presure and you know where its coming from get in front of the deer and set up an ambush on their escape route.