A trip like this is going to be expensive. It is pretty unavoidable, but there are certainly things that be done to reduce the costs.
Best overall money savings strategy. I know priceline.com spend a lot of time talking about how much they will save you, but it is true. Don’t be afraid to bid for a hotel. You may not know which specific hotel you will get, but in many respects it doesn’t matter. The star levels are pretty accurate and you can get amazing deals on hotels and cars. I. would recommend not going below 2 1/2 stars though.
Food Savings. You can go to Costco and buy stuff in bulk. This could be things like drink or snacks. You can also get stuff to microwave, many hotels have a microwave. Make sure you like it before you buy it though, otherwise you will end up with a lot of something you don’t like!
petrol. Costs for petrol can vary very widely while driving from one city to another. If you see cheap petrol fill up, particularly in remote areas. It is probably worth the extra time to fill up more often.
attractions try and buy things from groupon or online before you go. You will often save between 10 and 20 % off the prices you will pay at the door. The city passes are also available in specific cities. Not only do they save you money, but they also save you time on waiting in queues.