The Getty centre and Getty villa. Both free you just pay to park.15 bucks per car....book to reserve parking at the villa . Amazing views, delicious cafe with great views.....under ten bucks a meal. Free walking tours. The observatory Universal studios.80 bucks each but a good day out. In the summer the egyptian theatre does sat morning screenings of kid movies at 25 cents each...... Hollywood and highland centre is cheap parking if you validate in one of the cafes or shops.... 4 bucks. The walk on boardwalk from Santa Monica to Venice The annenburg beach house.....lovely outdoor pool....ten bucks each but Monday's in summer kids are free.....access to gym included in this Free tickets to a lot of shows like jay Leno or jimmy kimmel...Ellen show...just google them or find network websites
You can hike up to the back of the Hollywood sign....takes 3 hours but lovely hike. Driving along mulholland drive.......great views Griffith park has three open air mini railways... A few bucks to ride so sweet for kids and ponies for the same. Whale watching down at balboa....uncle Davey,s locker often do groupons....15$ per cruise. Check living social for deals for la too. San capistrano mission is lovely Laguna beach Crystal cove
Zuma beach is where bay watch was filmed and point dune beach is lovely too.
The hollywood bowl does amazing open air concerts in the summer....as low as 15 bucks each n you can take your own wine and picnic.
All theses chain eateries....you can eat as a family for between 15 and 30 dollars for all of you Panda express Soup plantation Sharkeys ....mexican In and out burger Chipolte
Trader joes does great food to cook with or just tasty pies....takeout salads? Hope that helps....it is an amazing city with loads to do.....best accessed with a car.you will have the best time. August and September too hot......October and November or spring is best here.
Depending on kids' ages, I would suggest buying tickets to a very American sports match in LA (not sure what season that would be, but Basketball/American Football/Baseball) to just get into the "American spirit".
Visit the Ground Zero site and reflecting pools Rockefeller Centre - good views from the top particularly on clear days A visit to the Radio City Music Hall (there is a great cupcake bakery nearby as well which is always packed out) Empire State Building (authorised people sell tickets outside so lines can be shorter if you buy from them) Walk through Central Park Museum of Modern Art Guggenheim Museum Walking along Fifth Avenue Riding the Staten Island Ferry (free) A visit to Macys Times Square Seeing a Broadway show
Some general counsel:- Forget Area 51 altogether; its about a 3 hour drive away from LV, you will be closely observed if you go anywhere near any restricted area (not always clearly marked). You will not see anything of any real interest and you could well end up getting arrested for your pains if you trespass.
I would not use a car in LV but instead walk, use taxis, ride the monorail that runs between the MGM Grand and the Hilton or public transport instead; road traffic can be horrendous on the Strip.
Where are you going to stay in LV?.
The Forum Shops at Caesars Palace and the Fashion Valley shopping mall are also worth a visit as is a trip to the outlet malls to the north and south of LV.
A trip to the Valley of Fire state park is well worth a visit; some companies do a day tour there (Pink Jeeps is one). You learn more that way as well from the guides about the place and the wildlife.
Hollywood Blvd is also a bit of a dive especially to the south of Manns Chinese theatre. Not glamorous at all.
It will take you around 3-4 hours to drive to San Diego Zoo; its a long way to go there for a day. Also you ideally need 2 days to make the most of the zoo as well, a lot of it is steep slopes and can be hard going in the heat.
Tijuana is a dump of a place; avoid at all costs. Again a long drive from where you will be staying in LA. You would be better off exploring more districts of LA instead.
I'd ditch the car hire at Vegas. Honestly. There is so much to see just on the strip and you only have 4 days. If you want to do anything outwith Vegas then a day trip to the canyon is worth every penny.
Fountains at Belagio of an evening, gondola ride in the Venetian and walking round the mall at ceasars. Most of all in Vegas just wander. See the casinos. They are massive. We spent a week in Vegas and could easily go back and see more.