At the risk of replying to myself.....I found how to get there from here. Not terribly well laid out on recreation.gov.
Use the search bar for "Mt. Whitney". Go to the Mt. Whitney page that has the button on the right for the lottery entry. Just adjacent is a button labeled "walk me through". Click this, takes you to a series of questions, which when you say that you are exiting through Whitney, will take you to a page to specify an entry location and permit availability, AND has a second tab for the Mt. Whitney exit permit and availability. Then the permit info and purchase page looks correct.
Hope this helps someone else as equally clueless as me,
Lewis
