This is a cool thing I just found from the Model 3 Owners Club new video.
1- go to www.tesla.com/build/models
2- while the page is loading (Chrome works best), stop the page from loading by pressing the X button that is normally the refresh button on the browser.
3- You will be sent to a page that looks like what the Model 3 configurator will look like. Super simple options with "packages" to choose from.
Let me know if anyone has any questions, very exciting stuff!