I disagree about driving being too difficult for someone that isn't local. I think it's fine for someone to drive. After all, you simply get on the 5 at Disneyland and get off the 5 at the Zoo Exit. (The Zoo is literally off the freeway in Griffith Park - right across from the Gene Autry museum - which you see the back of from the freeway. (We live in Burbank, 5 minutes from the zoo and this is our route to DL.)
The biggest thing to deal with when you consider is LA Traffic is that is can be slow and bogged down. I actually feel safer driving in LA Traffic than I did growing up and living most of my driving life in St. Louis, as it goes slower and more consistent. Keep in mind that rush hour is a bit longer here than most places. If you do the Zoo, you want to get back on the road to DL by 3pm to beat rush hour. Also, you want to stay in the middle lanes of traffic when on the 5, as there are different freeways that branch off. The 10 will go to the right and the 101 will be on the far left lane. When you go back south, the 5 will branch off to the left, but once again, not using the far left lanne - that is for the 60.