In general if you're under 18 you may have a hard time with the hotels, as noted with the credit cards.
A couple of things to check on..
- Do have your parents make the reservations ahead of time with a credit card number. The hotels are looking to make sure they get paid, so they're going to want a credit card number. In most cases if you want to, they'll take cash or travelers checks at the desk when you check out and then tear up the credit card slip in front of you if you pay cash.
- If you have a concern, have a written letter from a parent that includes credit card number, contact information on the parent (address, phone number), and a signature saying that you are authorized to charge to that card. They can even put a limit on it if they want to -- like $250/ time or something.
- If worse comes to worse (and I did this for a friend who didn't have a credit card and whose daughter got stuck in an airport hotel in a blizzard), your parents can fax in authorization to use a credit card to the hotel. They basically fax in the above written letter.
- If you want to go to Anaheim, there might be an issue with camping. I think there's a KOA campground in the vicinity of Disneyland, but other than that the closest campgrounds I know of are a ways away along the beach -- and they're set up for RV campers.
And besides the medical insurance bit, just in case of emergency --
- You're taking cell phones right? (I figured you were, but some people dont.) Make sure you check in. I-5 from Seattle to Anaheim has cell coverage pretty much the whole lenght of the way. This gives your parents piece of mind, and also lets you call for help if needed.
- Does anyone going along have a AAA or other roadside assistance card? It's another "just in case" precaution. But you know, something stupid can always happen -- even just locking your keys in the car. It's useful to have that available.
- Done your homework on maps and roads and stuff? And what to stuff in the car and what to take? Ice chest or food money and etc?
- Lastly, if you want to be treated as an adult, act like adult. Don't do something stupid. (Silly advice huh? But you'd be amazed at how many adults don't follow that....)