How much money do you think I would need?

Me and my cousin are going on a roadtrip in a year or so and we are going to California (from Louisiana). It's a 33 hour drive, because we're ping through Oklahoma and Utah and Nevada and all that so we can visit landmarks. We are planning to stay in Cali for about 2 weeks. The first week in the San Fran - Sacramento area and the next by Los Angeles and all the good stuff. We are going to Disneyland and Universal as well. On the way back we are leaving a different way, and going through Vegas, spending a night there, then going to the grand canyon and then leaving. A lot of things we are doing are just sightseeing, but there's also the things like amusement parks, tours, and the hotel cost. I'm 15 and my cousin is 20 and turning 21 in October so we will be able to stay in the hotels and all. But after a year of saving I will have around $1,000. How much do you think I will need, and whats some good ways for me to make some extra money I can spend on souvenirs and just shopping?? Thank you veeeeeery much!