The quickest way to get there, is win the Spider and Roadster Enduro (1 hour 15 minutes), take the 100,000cr, and pick up a Corvette Z06. Outfit it to win the European Championship in Amateur.
There is no tire wear, and you've got an easy field. Takes 20 minutes, and you can "Save and Re-load" to win the Vertigo. Sell that off, and you get 300,000+ the win. Do this 3 times (takes about an hour +) and you're over the million credit mark.
AO