USA - Road Trip, Suggestions?

That's a whole lot of driving! Florida to California is 3000 miles, and most of it is through Texas.
Now- we don't call them "caravan parks". You should look for RV (recreational vehicle) sites or the state and national parks, most of which have camping places for rent. Look up the parks in each of the states you're going to go through.

Ok, frankly, you really need to look at a map of the US and then you'll understand that your planned drives will result in you spending most of your time on the road, which frankly, is boring after the second hour.

You'd do far better to either fly or take the train between the main cities you want to visit, as then, either you would not tie up so much of your vacation in the travel, or, if on the train, you'd see a lot more from it, and not have to stop at night, so your total transit times will be far shorter than driving.

Driving, DC to Florida alone is three days, then at least two more to get to Texas, and four to get to LA from there. And, that's with no time available to stop and see things along the way.

Plus, a lot of car rental companies don't allow for such wide travel with their cars.

I will add (to the very fine answers!) that you do need to consider when you plan on making such a trip. Winging it at the wrong time of year or wrong weekend even can leave you high and dry accommodation wise in places. That SUCKS! A LOT! (I have encountered such circumstances)

Also before you arrive it may be a good idea to familiarize yourself with US road signs and rules if you have not driven here before. Generally they are not a heck of a lot different but trying to figure some out while speeding by in a car can be more challenging than necessary. (something else I learned too late)
You obviously know we drive on the right side. That takes a little getting use to but really should not be a big problem. Turn signals and windshield wipers will be. As will checking blind spots. Being on the other side of the car is not too bad when you are conscious of it. When you do things automatically (like signal for a turn) that's when it becomes amusing.

Drive carefully!! Have fun!

i hope one of you are over 25 years of age or you will have a hard time renting a car. and it is going to cost you thousands of dollars to rent a car for 4 weeks and drive it from one coast and drop it off at the other because you aren't american and you might sneak home if something bad happens. i did a fake booking for a economy car from enterprise for 4 weeks in march from washington dc airport to los angeles and it was $2500 and for over age 25+.

http://www.cruiseamerica.com/rent/hot_deals/
here is something that may actually be cheaper. a rv/motorhome or what you probably call a caravan for part of your trip doing it one way dropping it off where the company wants it. one bit of advice. if you do a new unit delivery from the factory do not just drop the unit off at the location and let some manager say they will fill out the paperwork and do the inspection later. you wait and pester them however long it takes to have the paperwork done and signed and everything checked so no one later later lies and says you damaged something and they scam while blaming you.

If you just want to drive, stay in Australia and drive. Your interior probably looks a lot like Texas (hot, dry, and barren). If you want to have a real vacation experience pick a quarter section of the U S and thoroughly enjoy it. The route you mention misses much of the U S (i e the northern states and their beauty and attractions). The south is hot and humid during the summer. [<that was worth repeating.]

w