My daughter did this same project a few years ago.
Here's how she approached it.
She decided to do a Disney around the world.
There were 25 kids in her class, and each kid was allowed to bring 1 other person with them, for a total of 50 people.
We "booked" 50 seats on the Concorde (can't do this anymore, but you could book them first class--it uses up more money). We used Orbitz, Expedia and United websites for exact prices. The 50 people flew to France to visit
Disneyland Paris. We found ticket and hotel prices on the website and also through a
travel agent. Also, don't forget limos from the airport to the hotel. We budgeted $150/day per family for food (this can be adjusted up or down if you have money left at the end).
Then we found airfare to Tokyo Disney, and booked hotel rooms and limos there, adding the cost of tickets and food.
We then booked airfare to Disneyland, 25 rooms at the Grand Californian, tickets and limos from the airport.
From there we booked the same for WDW, including 25 rooms at the Grand Floridian, using the prices found on the WDW website.
Each family was given a new set of luggage, prices were found at Kohls.com, I believe. Each family was also given a digital camera, with prices found at a local camera store.
We then totalled up how much we spent, subtracted the total from the one million and then divided the balance between the 50 people for souvenier money.
It's been awhile since we did this, so I may have forgotten something. If you need any more help or suggestions, please let me know. I may even have the project floating around the house somewhere.
I have to say, this is definitely not a project most kids could do on their own. Most companies don't take kids seriously when they call for prices and such. I usually don't help my kids with projects, but they really do need assistance on this one. Good luck!
